describe a weather station that will be used to collect weather data it should collect data that are needed to make forecasts. explain what data are needed how the station would be powered and any other relevant information . Then sketch it out
(please draw a sketch arigato)

Answers

Answer 1

The weather station is a place which contain instrument that collect data of atmospheric pressure, wind, humidity, etc to forecast weather. The weather station is powered by solar power.

What is a weather station?

A weather station is a place that measure atmospheric conditions, on the basis of temp., pressure, wind speed, etc conditions.

They can be based either in land or sea. They are necessary to forecast any disaster, so we can prepare for the disaster.

Thus, the weather station is a place which contain instrument that collect data of atmospheric pressure, wind, humidity, etc to forecast weather. The weather station is powered by solar power.

Learn more about weather station

https://brainly.com/question/26164593

#SPJ1


Related Questions

Consider the following representation of a reaction mechanism.
Step 1: A+ AC + E (slow)
Step 2: E+BA+ D (fast)
Overall reaction: A + B C + D
→>>
What should appear in the rate law for the reaction above?
O only A and B because they are reactants in the overall reaction
only C and C because they are products in the overall reaction
only A because it is the reactant in the rate-determining step
O only E and B because they are the reactants in the rate-determining step

Answers

The rate law depends on only A because it is the reactant in the rate-determining step.

What is the rate law;

The rate law is a representation of the rate of reaction. The fast reaction is  E+B ------> A+ D. The slow reaction is A + A ----->C + E. The overall reaction is A + B ------> C + D.

We know that the rate law depends  only on the  the slow reaction hence the rate law depends on only A because it is the reactant in the rate-determining step.

Learn more about the rate law:https://brainly.com/question/4222261

#SPJ1

show the step by step hybridization of hydroxonium ion H3O, draw the diagram showing the geometry and the bond angle​

Answers

The central oxygen atom is a state of sp3 hybridization having only one available lone pair.

What is hybridization?

The term hybridization refers to the mixing of two or more atomic orbitals to yield hybrid orbitals that are suitable for bonding.

Looking at the ion H3O^+, we can see that the central oxygen atom is a state of sp3 hybridization having only one available lone pair. The image of the ion is shown here.

Learn more about hybridization in ions:https://brainly.com/question/16556024

#SPJ1

- If x moles of electrons are transferred when 4.8 g of oxygen reacts with 4.8 g of
magnesium, what is the value of x?

Answers

Answer:

sdfffffffff

Explanation:

dfffffgsdsdsdsdsdsdsdsdsdsdsdsdsdsdsd

What is the pH of a 0.034 M
solution hydroiodic acid (HI)?
pH = [?]

Answers


Answer
1.4685210829577449

Answer:

1.47

Explanation:

acellus

Why would you use a solution, such as a cabbage ph indicator, to measure the ph of household items?.

Answers

Answer:

Discussion: Red cabbage is useful as a pH indicator because the leaves contain a pigment molecule from the family of anthocyanins (shown below) which are responsible for many of the red/purple/blue colors observed in fruits and vegetables. In neutral solutions, the color observed is purple.

hope this helps:3

Which is an unreliable source?

A scientist who studies dinosaurs presents her research on velociraptors at a science convention.
An advertisement for acne medication claims it can clear up acne in less than one week.
An article on the Centers for Disease Control and Prevention (CDC) website discusses the salmonella bacteria.
A chemistry teacher discusses possible projects for the upcoming science fair.

Answers

The source that is unreliable is an advertisement for acne medication claims it can clear up acne in less than one week.

What are citable sources?

Citable sources are those sources that are gotten from places that are proven to be of good standards and not from mere claims such as:

Science journals

professional organizations

government agencies

Therefore, the source that is unreliable is an advertisement for acne medication claims it can clear up acne in less than one week.

Learn more about citations here:

https://brainly.com/question/8130130

#SPJ1

How many grams do 6.534e+24 molecules of phosphoric acid weigh?

Answers

Answer:

1,063 grams H₃PO₄

Explanation:

To find the mass of phosphoric acid (H₃PO₄), you should (1) convert molecules to moles (via Avogadro's number) and then (2) convert moles to grams (via molar mass from periodic table).

Molar Mass (H₃PO₄): 3(1.008 g/mol) + 30.974 g/mol + 4(15.998 g/mol)

Molar Mas (H₃PO₄): 97.99 g/mol

6.534 x 10²⁴ molecules H₃PO₄                       1 mole                         97.99 g
---------------------------------------------  x  -------------------------------------  x  --------------
                                                            6.022 x 10²³ molecules          1 mole

= 1,063 grams HPO

Which statement best describes what makes a base weak

Answers

The statement that describes what makes a base weak is that the base will be unable to dissociate completely in water.

What is a base?

A base is any of a class of generally water-soluble compounds, having bitter taste, that turn red litmus blue, and react with acids to form salts.

Bases usually dissociate into hydroxide ions (OH-) when in an aqueous solution.

However, a base is termed weak or strong depending on it's ability to dissociate completely. A weak base does not dissociate completely into hydroxide ions when in an aqueous solution.

Learn more about bases at: https://brainly.com/question/23687757

#SPJ1

Convert 7.50 mol of Li₂O to grams

Answers

Answer:

223.5 g

Explanation:

The formula between the number of moles, mass and Mr can be used to convert moles to grams.

Number of moles = mass ÷ Mr

So, mass = number of moles × Mr

  Mr of Li₂O = (6.9 × 2) + 16 = 29.8

∴ Mass = 7.5 × 29.8 = 223.5 g

3) Convert 0.987 moles of Lithium to grams.

Answers

Answer:

6.850767 grams is the answer

[tex]0.987 ~ \text{moles of Li} = 0.987 \times \text{Molar mass of Li}\\\\~~~~~~~~~~~~~~~~~~~~~~~=0.987 \times 6.941~ g\\\\~~~~~~~~~~~~~~~~~~~~~~~=6.850767~ g[/tex]

When water, oxygen, and iron
combine, what is produced?
A. rust
B. carbon
C. carbon dioxide
D. carbon monoxide

Answers

A. Rust.
The chemical reaction that happens between these three is very slow as none of these have opposite valence electron charges

Answer:

When we combine oxygen, and iron rust is produce.

Explanation:

The iron reacts with water and oxygen to form hydrated iron(III) oxide, which we see as rust. Iron and steel rust when they come into contact with water and oxygen – both are needed for rusting to occur.

How many moles of water (H2O) does 10.82 x 1023 molecules represent? Round your answer to the hundredths place.

Answers

No of moles

[tex]\\ \rm\Rrightarrow \dfrac{No\:of\: molecules}{Avagadro\:no}[/tex]

[tex]\\ \rm\Rrightarrow \dfrac{10.82\times 10^{23}}{6.023\times 10^{23}}[/tex]

[tex]\\ \rm\Rrightarrow 1.80mol[/tex]

No of molecules given=10.82×10²³

So

[tex]\boxed{\sf No\:of\: molecules=No\:of\:moles\times Avagadro\:no}[/tex]

[tex]\\ \tt{:}\longrightarrow 10.82\times 10^{23}=n\times 6.023\times 10^{23}[/tex]

[tex]\\ \tt{:}\longrightarrow n=\dfrac{10.82}{6.023}[/tex]

[tex]\\ \tt{:}\longrightarrow n=1.8mol[/tex]

2.70 L of a gas has a pressure of 0.63 atm. What is the volume of the gas at 105kPa?

Answers

[tex]\huge{\green}\fcolorbox{blue}{black}{\bf{\underline{\red{\color{brown}Answer}}}}[/tex]

4.44l

Explanation:

[tex] \sf Volume \: of \: gas \: before(V_1) = 2.7 \: l \\ \sf Pressure \: of \: gas \: before(P_1) = 0.63 \: atm \\ \sf 0.63 \times 101.3 = 63.8 \: kPa \\ \sf Volume \: of \: gas \: after(V_2) = ? \\ \sf Pressure \: of \: gas \: after( P_2) = 105 \: kPa[/tex]

[tex] \textsf{ By using Boyle's law} \\ \\ \tt{ \frac{P_1}{V_1} = \frac{P_2}{V_2} }[/tex]

[tex] \sf \longrightarrow \frac{2.70}{63.8} = \frac{V_2}{105} \\ \\ \\ \sf \longrightarrow \frac{2.7 \times 105}{63.8} = V_2 \\ \\ \\ \sf \longrightarrow \frac{283.5}{63.8} = V_2 \\ \\ \\ {\orange {\boxed{ \longrightarrow 4.44 \: l = V_2}}}[/tex]

Which statement best describes the role of oxygen in cellular respiration?
OA. Oxygen molecules are a waste product of electron flow.
B. Oxygen molecules form as ATP molecules are made.
OC. Oxygen molecules form as sugar molecules are broken down.
OD. Oxygen molecules are used to make water molecules.

Answers

The role of oxygen in cellular respiration is to make water molecules. hence, option (D) is correct.

What is Cellular respiration ?

Cellular respiration is the process in which cells break down molecules for energy.

The cells use oxygen to break down food in the form of glucose to produce water and release carbon dioxide.

During aerobic cellular respiration, glucose reacts with oxygen, forming ATP that can be used by the cell. Carbon dioxide and water are created as byproducts.

In this reaction, energy is produced in the form of ATP that is used by the cell for its various activities.

Thus the correct answer is option D.

Learn more about respiration here ;

https://brainly.com/question/12605249

#SPJ1

How much energy is wasted by a 10% efficient filament bulb with 5 J of input?​

Answers

Answer:

4.5 J wasted

Explanation:

10 % efficient means 90% wasted

90% of 5 J   =  .9 *5 = 4.5 J

of an investigation, students were asked to prepare a sodium hydroxide solution of a certain molarity. The students were given a
of procedures. Which procedure will result in 750 mL of 1.5 M NaOH solution?
issolving 1.13 g of NaOH in enough water to make up to 750 mL of solution
ssolving 45 g of NaOH in enough water to make up to 750 mL of solution
ssolving 40 g of NaOH in 1 L of water
solving 1.13 g of NaOH in 0.750 L of water

Answers

The correct procedure is:

Dissolving 45 g of NaOH in enough water to make up to 750 mL of solution

What is molarity?

This is defined as the mole of solute per unit litre of solution. Mathematically, it can be expressed as:

Molarity = mole / Volume

How to determine the mole of NaOH Volume = 750 mL = 750 / 1000 = 0.75 L Molarity = 1.5 MMole of NaOH =?

Mole = Molarity x Volume

Mole of NaOH = 1.5 × 0.75

Mole of NaOH = 1.125 mole

How to determine the mass of NaOH Mole of NaOH = 1.125 moleMolar mass of NaOH = 40 g/mol Mass of NaOH =?

Mass = mole × molar mass

Mass of NaOH = 1.125 × 40

Mass of NaOH = 45 g

Thus, to obtain 750 mL of 1.5 M NaOH solution, 45 g of NaOH will be dissolved in enough water to make up to 750 mL of solution

Learn more about molarity:

https://brainly.com/question/15370276

#SPJ1

The "iodine clock reaction" is a popular chemical demonstration. As part of that demonstration, the I−3 ion is generated in the reaction

S2O2−8(aq)+3I−(aq)⟶2SO2−4(aq)+I−3(aq)

In one trial, the unique rate of reaction was 6.93 μmol⋅L−1⋅s−1. What was the rate of reaction of iodide ions?
1. Initial Rate = _______ μmol⋅L−1⋅s−1 ??????

What was the rate of formation of sulfate ions?
2. Rate of formation = _______ μmol⋅L−1⋅s−1 ??????

Answers

In one trial, the unique rate of reaction was 6.93 μmol⋅L−1⋅s−1, the initial rate is 17.4 μmol⋅[tex]l^-^1[/tex]⋅[tex]s^-^1[/tex] and rate of formation of sulfate ions was 11.6 μmol⋅[tex]l^-^1[/tex]⋅[tex]s^-^1[/tex]

What is the rate of recation?

Reaction rate, in chemistry, is the speed at which a chemical reaction proceeds.

[tex](S_2O_8)^-^2 (aq) + 3 I^-(aq)[/tex] → [tex]2 S0_4^-^2 (aq) + 3I^- (aq)[/tex]

Rate of the reaction = -Δ [[tex]S_20_8^-^2[/tex]] /Δ t = -1/3 Δ [[tex]I^-[/tex]] /Δ t

5.8  μmol⋅[tex]l^-^1[/tex]⋅[tex]s^-^1[/tex] = -1/3 Δ [[tex]I^-[/tex]] /Δ t

-Δ [[tex]I^-[/tex]] /Δ t =17.4 μmol⋅[tex]l^-^1[/tex]⋅[tex]s^-^1[/tex]

So the rate of reaction of iodide ion =17.4 μmol⋅[tex]l^-^1[/tex]⋅[tex]s^-^1[/tex]

+1/2Δ [[tex]S0_4^-^2[/tex]] /Δ t  = rate of reaction

+1/2Δ [[tex]S0_4^-^2[/tex]] /Δ t  = 5.8 μmol⋅[tex]l^-^1[/tex]⋅[tex]s^-^1[/tex]

+ Δ [[tex]S0_4^-^2[/tex]] /Δ t  = 5.8 X 2 = 11.6 μmol⋅[tex]l^-^1[/tex]⋅[tex]s^-^1[/tex]

Rate of formation of sulfate ions=11.6 μmol⋅[tex]l^-^1[/tex]⋅[tex]s^-^1[/tex]

Hence, the initial rate is 17.4 μmol⋅[tex]l^-^1[/tex]⋅[tex]s^-^1[/tex] and rate of formation of sulfate ions was 11.6 μmol⋅[tex]l^-^1[/tex]⋅[tex]s^-^1[/tex]

Learn more about the rate of reaction here:

https://brainly.com/question/13228022

#SPJ1

What is the density of helium at 0.975 atm and 27.0 C?

Answers

Answer:

0.158g/L.

Explanation:

MM of helium gas or He =4 g/mol

P = 0.974 atm

T = 27 °C, but we need absolute temperature.

TK = TC + 273

T = 27 + 273 = 300 K

m/V = (4 g/mol · 0.975 atm) / (0.0821 L·atm/mol·K · 300 K)

m/V = 0.975/6.1575 g/L

m/V = 0.158g/L

Answer: The density of the helium is 0.158g/L.

Convert 26.02 x 1023 molecules of C2H8 to grams. Round your answer to the hundredths place.

Answers

No of molecules=26.02×10²³molecules

No of moles

26.02×10²³/6.023×10²³4.3mol

Molar mass

C2H82(12)+8(1)24+832g/mol

Mass

Moles×Molar mass32(4.3)137.6g

[tex]\\ \tt{:}\longrightarrow No\:of\:moles=\dfrac{Molecules}{Avagadro\:no}[/tex]

[tex]\\ \tt{:}\longrightarrow No\:of\:moles=\dfrac{26.02\times 10^{23}}{6.023\times 10^{23}}[/tex]

[tex]\\ \tt{:}\longrightarrow No\:of\:moles=4.32mol[/tex]

Molar mass of Ethane=32g/mol

We need the mass

[tex]\\ \tt{:}\longrightarrow No\:of\:moles\times molar\:mass[/tex]

[tex]\\ \tt{:}\longrightarrow 32(4.32)[/tex]

[tex]\\ \tt{:}\longrightarrow 138.24g[/tex]

Which phase has the lowest entropy?
O A. Aqueous
O B. Liquid
O C. Solid
O D. Gas

Answers

Answer:

Solid have the lowest entropy

A certain atom has 22 protons and 19 electrons. This atom loses an electron. The net charge on the atom is now 4+. If this same atom with 22 protons and 19 electrons were to gain 3 electrons, the net charge on the atom would be

Answers

Answer: 0

Explanation:

If 3 electrons were to be gained, then the number of protons would equal the number of electrons.

Find the pressure in mm HG produced by 2.35 g of carbon dioxide in a 5.00 L flask at 18 C?

Answers

Answer:

194 mm Hg or 193.8mm Hg

Explanation:

273+18=291 K

2.35g /44

=0.0534 moles

P=0.0534 mol×0.082×29 / 5L

=0.2548 atm

0.255 × 760

=193.8 mmHg

What is the mass number of a single atom of magnesium-25?

Answers

Answer: It is approximately 24.985837

Question 5 of 20:
Select the best answer for the question.
5. When considering gravity acceleration and the force of acceleration, what must be true?
O A. The direction of acceleration must be perpendicular to the direction of the force.
O B. The direction of the force and the direction of acceleration must be opposite of each other.
OC. The direction of the force and the direction of acceleration must be the same as each other.
O D. The mass of the body must be the same as the acceleration of the body.
Mark for review (Will be highlighted on the review page)
<< Previous Question
Next Question >>

Answers

( 5) direction should same in first than opposite in last

Analyze the word problem and match the vocabulary terms to the chemicals in the word problem.

5.00 grams of solid citric acid is dissolved in 500.00 ml of water to make aqueous citric acid

Answers

5.00 grams of solid citric acid (solute) is dissolved in 500.00 ml of water (solvent) to make aqueous citric acid (solution).

What is a solution?

A solution is a homogeneous mixture prepared by dissolving a solute in a solvent.

5.00 grams of solid citric acid is dissolved in 500.00 ml of water to make aqueous citric acid.

In this example:

5.00 grams of solid citric acid is the solute (what is dissolved).500.00 ml of water is the solvent (the media in which the solute is dissolved).Aqueous citric acid is the resulting solution.

5.00 grams of solid citric acid (solute) is dissolved in 500.00 ml of water (solvent) to make aqueous citric acid (solution).

Learn more about solutions here: https://brainly.com/question/25326161

#SPJ1



Why do you think it is
important to group substances and mixtures based on their classifications or uses?

Answers

The purpose of classification is to identify objects with common or similar properties.

What is a mixture?

A mixture is composed of one or more pure substances in varying compositions.

It's important for scientists to know the properties of matter because all things are made up of matter.

Each type of matter has different physical characteristics and scientists need to know and understand these characteristics to make calculations.

The main phases of matter are solid liquid and gas.

Hence, the purpose of classification is to identify objects with common or similar properties.

Learn more about the mixture here:

https://brainly.com/question/24898889

#SPJ1

All else being equal, air volume increases when pressure decreases. Use this relationship to explain why warm air at the equator rises up through the less dense air above it.

Answers

The relation between the volume and the pressure of the gas can be given by the ideal gas equation. Warm air has more volume and low pressure that makes them rise above the equator.

What is atmospheric pressure?

Pressure present and exerted by the atmospheric gases are called atmospheric pressure. The volume of the gas is in inverse relation to the pressure of the gas.

Warm air has a high volume compared to cold air. More volume results in low pressure making them rise above the dense layer of the equator region.

Therefore, the warm air rises due to a decrease in pressure.

Learn more about the pressure here:

https://brainly.com/question/25429027

#SPJ1

How many moles of MgCl2 where needed to make a 650.0 mL solution a concentration of 0.962 M?

Answers

Answer:

0.625 moles MgCl₂

Explanation:

Since you were given a molarity value and volume, you should use the molarity equation to find moles. The equation looks like this:

Molarity (M) = moles / volume (L)

To find moles, you need to (1) convert mL to L (by dividing by 1,000) and then (2) plug the numbers into the formula and simplify to find moles. The final answer should have 3 sig figs as the lowest amount of sig figs in a given value is 3.

Step 1:

650.0 mL / 1,000 = 0.6500 L

Step 2:

Molarity = moles / volume

0.962 M = moles / 0.6500 L

(0.962 M) x (0.6500 L) = moles

0.625 = moles

noltoupe sonblod
Example: Ksp for cadmium carbonate is 1.8 * 10-14, calculate
the equilibrium solubility of cadmium carbonate in a solution at
constant pH of 11?
For H₂CO3
1- Ka = 4.45 * 10-7
2-ka =4.7*10-11

Answers

The equilibrium solubility of cadmium carbonate in a solution at constant pH of 11 is 1.65 x 10⁻⁵ mol/dm³.

Equilibrium solubility of the compound

The equilibrium solubility of cadmium carbonate in a solution at constant pH of 11 is calculated as follows;

H₂CO3 ⇄ 2H⁺  + CO₃²⁻

x         :      2x        x

ksp = (2x)²x

ksp = 4x³

(1.8 x 10⁻¹⁴) = 4x³

(1.8 x 10⁻¹⁴) /4 = x³

4.5 x 10⁻¹⁵ = x³

x = (4.5 x 10⁻¹⁵)^¹/₃

x = 1.65 x 10⁻⁵ mol/dm³

Thus, the equilibrium solubility of cadmium carbonate in a solution at constant pH of 11 is 1.65 x 10⁻⁵ mol/dm³.

Learn more about equilibrium solubility here: https://brainly.com/question/23946616

#SPJ1

The equilibrium solubility of cadmium carbonate in a solution at constant pH of 11 is 1.65 x 10⁻⁵ mol/dm³.

What is solubility?

Solubility is defined as the maximum amount of a substance that will dissolve in a given amount of solvent at a specified temperature.

The equilibrium solubility of cadmium carbonate in a solution at constant pH of 11 is calculated as follows;

H₂CO3 ⇄ 2H⁺  + CO₃²⁻

x         :      2x        x

ksp = (2x)²x

ksp = 4x³

(1.8 x 10⁻¹⁴) = 4x³

(1.8 x 10⁻¹⁴) /4 =

4.5 x 10⁻¹⁵ = x³

x = [tex](4.5 X 10^{-15})^{\frac{1}{3} }[/tex]

x = 1.65 x 10⁻⁵ mol/dm³

Thus, the equilibrium solubility of cadmium carbonate in a solution at constant pH of 11 is 1.65 x 10⁻⁵ mol/dm³.

Learn more about equilibrium solubility here:

brainly.com/question/23946616

#SPJ1

Temperature Change Curing Phase Change (5 pts)
Water boils at 100 °C. You boil a pot containing 500 g of water for 10 minutes.

What is the temperature of the water after 10 minutes of constant boiling? (Hint this question does not require any math).

Explain your answer by discussing heat and state change.

Answers

Answer:

since water boil at 100 °C .so 500gof water Will still boil at 100 °C

Other Questions
Which of the following is a complex number?OA. -8-3/1/2OB. 3/+95OC. 9-17OD. 5-2V7274 155. At the Redbridge School, of pupils have a pet dog, & have a cat and have aThe rest have no pets.A)What fraction of the children has no pet? Write this in its simplest form. B)There are 250 pupils at the School. How many children have no pets?C)At the Bluebell School, 23% have no pets. What percentage increase of pupils atthe Bluebell School have no pets compared to the Redbridge School? According to Machiavelli, what should be the two amis of a prince Uv has endpoints at u(4, 6) and v(10, 4). find the midpoint m of uv. write the coordinates as decimals or integers. m = submit In general, what happens to the hormone levels between days 21 and 27, just prior to menstruation if the egg was not fertilized? hormone levels generally decrease. hormone levels generally rise. hormone levels remain the same. hormone levels go in two different directions. 11/12 - 7/9 5/365/7225/3625/72 i need this people. Please help, thanks!!! Who does the artist believe really carries the burden of white imperialism and colonization? what details in the cartoon lead you to this conclusion? Find an algebraic expression equivalent to 3 over 2 left paren 6 x squared minus two over 3 x right paren Dyson cordless vacuum cleaners offer heavy-duty performance for cleaning all floor types. The Dyson is also very lightweight and versatile. The price for the basic Dyson model is $599. Because the Dyson provides the user with really clean floors and carpets, the Dyson is an example of _______. Suppose you have entered 97-mile biathlon that consists of a run and a bicycle race. During your run, your average velocity is 8 miles per hour, and during your bicycle race, your average velocity is 27 miles per hour. You finish the race in 5 hours. What is the distance of the run? What is the distance of the bicycle race? A chef randomly pulls cupcakes from a box containing 6 cupcakes of the same shape and size. There is 1 cupcake with vanilla frosting, 3 cupcakes with chocolate frosting, and 2 cupcakes with pink frosting. He draws 1 cupcake and then draws out another cupcake without replacing the first one. Find the probability of picking 1 cupcake with chocolate frosting followed by another cupcake with chocolate frosting, and show the equation used, and solve it. Whic the following is an angle? (3 pointsFigure A has two rays connected at a vertex, Figure B is a line with one endpoint and the other end has an arrow, Figure C is a line with two endpoints, and Figure D is a line with an arrow at each endFigure AFigure BFigure CFigure D Translate the shape A three squares right and one square down.What are the coordinates of the vertices of the image? In which number does the digit 3 have a value that is ten times greater than the value of the digit 3 in the number 145,317? Ayuda porfa doy corona A manager finds a moderate negative correlation between the number of computer sales and the number of microwave sales in his store.Which statement is true?The correlation is most likely a coincidence.The correlation is most likely due to a lurking variable.The correlation is most likely a causation. When a sociologist actually joins a group for a period of time to gain an accurate sense of that group's operations, this approach is known as Which types of conflict can you infer from the previous passage?