Topic related to air travel would most likely be studied by a biologist?

The correct answer is the spread of disease among the passengers.  

Explanation:

A biologist who studies the spread of disease among the passengers traveling in a flight would be an epidemiologist. An epidemiologist refers to a scientist who examine studies within the populations of individuals. These are the public health professionals who assess the outbreaks of the disease in order to cure the prevailing diseases and to inhibit the outbreaks in future. They are regarded as the disease detectives of the public health world.  

the organisms are not adapted to live in some communities or habitats.

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.