You are maintaining a small population of fruit flies in the laboratory by transferring the flies to a new culture bottle after
each generation. After several generations, you notice that the viability of the flies has decreased greatly. Recognizing that small population size is likely to be linked to decreased viability, the best way to reverse this trend is toa. change the temperature at which you rear the flies.b. transfer only the largest flies. c. reduce the number of flies that you transfer at each generation.
d. shock the flies with a brief treatment of heat or cold to make them more hardy.
e. cross your flies with flies from another lab.
The given small population of flies is exhibiting loss of genetic variations due to small population size leading to reduced viability. The populations with small size often exhibit loss of vigor due to reduced genetic variability. The loss of viability as caused by loss of genetic variations can be overcome by out-crossing. In out-crossing, the related individuals with no common ancestors for at least 5-6 generations are crossed.
Out-crossing increases the genetic variations and thereby, restores the lost viability of the population. Therefore, the population of flies should be allowed to mate with the flies from another lab to increase genetic variations and thereby, the viability of the progeny.
The answer is body's physiological reaction to any demand that is placed on it
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Hans selye describe a stress as responses of the body to any changes of demand. The response of the body to the demand could be harmful as it could lead to some disease like stomach ulcer. It is important to know what your stress source and manage it before the stress start to harm your body.
The main function of the respiratory system is to allow the exchange of gases between the atmosphere and the lungs. Hence,the only structure that carries out this function is the alveoli as other structures such as the nose,trachea and pharynx transport gases to the alveoli just so that it can can out its function.
