For the 1st one with the Cheetah: It would be a long tail because it helps them balance when they turn. Sinch Cheetahs move extremely quickly they need a balance to ensure they don't topple over when they turn, this tail provides this balance.
For the 2nd one with the bear: Thick coats on a bare will help provide warmth whenever they go to hybernate. Thin fur would leave room for freezing and wouldn't be able to help them maintain the proper body temperature.
The 3rd one with the clownfish: A round tail provides a bigger boost when swimming since it is able to push more water. A forked tail would create a gap when they swim so they would have to expend more energy than with a round tail.
The 4th one with the Finch: Since grubs live underground a thinner beak would be able to dig them out and stab them faster. This allows them to reach farther and get more food.
Cells get energy for their functioning through sunlight and other organic food molecules. ATP is a good example of energy pathways through photosynthesis.
