Answer;
A. leaf to mouse
Explanation;
-Considering the fact that the amount of energy at each trophic level reduces as it moves through an ecosystem from the lowest trophic level which happens to be producers (plants). And about 10 percent of this energy at any trophic level is transferred to the next level since the rest is lost largely through metabolic processes as heat.
-It means that the lower the trophic level the higher the energy obtained, for instance from producers to primary consumers, more energy is passed since it is the first passage of energy.
Answer:
Blood is carried away from the heart by arteries. Blood that is rich in oxygen. Blood that is low in oxygen is returned to the heart by veins. there is more pressure in arteries than in veins.
The answer is A. Excretion I hope this helps