Which of the following is a food chain in the food web shown in the figure below?

Lesson 3: Movement of Energy in Ecosystems

Explanation:

1. B. grass,grasshopper,snake hawk

2. D. eliminated as heat

3. C. river

4. A. Biomass at the fourth trophic level is approximately ten times smaller than biomass at the trophic level.

the correct answer is: b. pantala flavescens, because these organisms would have a high level of genetic variation due to sexual reproduction.  

because involves two organisms (parents) whose genetic material combines, sexual reproduction leads to genetic variation in new generations of offspring. the offspring is an unique organism, with new genome, more protected with the higher ability to adapted. this process is fundamental to evolution.