If a rabbit receives 150 calories of energy from eating carrots, how much of
that energy would be passed on to a snake in the following food chain?
carrot - rabbit - snake - hawk

According to the 10% law of energy transfer, only about 10% of energy will be transferred to the successive level from the previous trophic level. Therefore according to this law carrot will have the highest energy level as it is present at the lowest trophic level.

Then it will transfer 10% of its consumed energy to the rabbit and then snakes will get 10% energy of rabbit after consuming it. Therefore if the energy amount is given it can be calculated by dividing it by 10 for upper trophic level.

So if a rabbit receives 150 calories of energy from eating carrots it will pass only 15(150/10=15) calory of energy on to a snake. Therefore the correct answer is 15 calories of energy would be passed on to a snake in the following food chain.

b c a d mark me

the answer is true when observing or determining population size, a direct observation is use, in which each organism is counted in a population or in an area. one benefit of this measure is that you get the exact population count but it will take a long time to  determine  the  size  of a  population.