Question

AP BIOLOGY EXPLANATION PLEASE! <3

Hey guys, I know the correct answer, but I need some assistance understanding WHY it is correct and how to come to that answer! Thank you!

A porcupine eats 3000 J of plant material. Of this, 2100 J is indigestible and is eliminated as feces, 800 J are used in cellular respiration, and 100 J are used for growth and reproduction. What is the approximate production efficiency of this animal?

0.03%

2.7%

3%

33%

Answer 1

The answer is 3%.

There's 100 J for growth from a total of 3000J ingested. To find out what percentage of J are used for growth, you need to figure out how much 100 of 3000 is. To do this, you divide 100/3000=0.0333. To turn it into a percent, you have to times it by 100 again, so 0.0333 x 100 = 3.33.