C
The atomic mass is the sum of the number of neutrons and protons.
<h2>Answer:</h2>
The option C is the correct answer.
Which is, "He varies the nitrogen and carbon dioxide levels in the air from one trial to the next".
<h3>Explanation:</h3>
The hypothesis of Malik was about the effect of increased oxygen level on the growth of the red-legged grasshoppers.
So the areas of his experiment should be the:
- Grasshopper type.
- High oxygen level.
- Rate of growth of grasshopper.
So all the given options are relevant to his experiment except the third one.
So varying the nitrogen and carbon dioxide level in air could not contribute in his experiment.
<h2 />
Answer:
Find two boxes just a bit smaller than the other. The long sides of the box should be less than twice as long as the short side of the boxes. The smaller box should fit inside the larger box with about 1 inch in each direction to spare. The boxes can be cut down so that they fit together properly. Leave the flaps on the boxes. Buy a small sheet of Plexiglas (tm) a little bit smaller than the width and length of the top of the box. You will also need four pieces of cardboard to use for reflectors.
Explanation:
The pressure at the depth h in the ocean is given by (Stevin's law)

where

is the atmospheric pressure
and

is the pressure exerted by the column of water of height h=4267 m, with

being the water density and

.
Substituting, we find

We want to convert this into atmospheres: we know that 1 atm corresponds to the atmospheric pressure at sea level, so

, therefore we just need to divide by this number: