Which physical system includes all plants, animals, and people?
a. atmosphere
b. biosphere
c. lithosphere
d. hydrosphere

Biosphere

Explanation:

The biosphere is the name that is given to the sum of all ecosystems. The biosphere is the system that includes all living beings and their relationships. This sphere interacts with others such as the atmosphere, the lithosphere, the geosphere and the hydrosphere. Therefore, this is the physical system that includes all plants, animals and people.

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.