Kate gathered three boxes of the same size made of different materials: glass, clear plastic, and aluminum painted black. she placed them on a window sill in the sun for an hour then measured the warmth of the air in each box. in this experiment, the warmth of the air is a( a. independent variable b. control c. dependent d. constant

I am sure that the answer is C dependent

In the given experiment there are three factors

a) type of material : these are independent of each other so are independent variable

b) time : one hour : we have a fixed time so this a constant

c) warmth of air : it is dependent on the time and also on the material of the boxes taken for keeping the air in sun. Thus answer is "Dependent"

they are made of gases.

they have a spherical shape.

they make energy through fusion.

the best answer is d because the strong cohesion is caused by the ability of water molecules to undergo hydrogen bonding.

a is incorrect because when water solidifies, it becomes   ice, which expands and occupies a bigger volume for the same mass of water in its liquid state.

b is incorrect because water has high surface tension. besides bonding to itself it hydrogen bonds to other molecules at the top decreasing possibility for breaking of attractive forces.

c is incorrect because the water molecule has oxygen which is highly electronegative and so pulls the electron pair towards itself creating a dipole moment, making the molecule polar.

e is incorrect because water has strong adhesion, ability to stick to other molecules such as glass because of this molecules having stronger hydrogen bonding than water.