Answer:
Option A. Gases are compressible and have a variable shape.
Explanation:
From the knowledge of kinetic theory of matter, we understood that the force of attraction between gases molecules are negligible and this makes the gas molecules to be far apart. With this character, they can easily be compressed. Since the molecules of gas are far apart, they have no fixed shape, but tends to assume the shape of the container they are placed.
Largest to smallest: barium, calcium, selenium, oxygen
B when the amount of available plankton is greatly reduced. This would increase fighting among fish for food.
Mass pendulum hope i helped if thats the answer