Which of the following occurs most often in a population when genetic variation and overproduction are present? some organisms have a lower reproductive success than others. some organisms have a higher reproductive success than others. some organisms have no reproductive success. some organisms do not have genetic variation.

Option B, Some organisms have a higher reproductive success than others.

Explanation:

Over production is a scenario where an individual produce more than the normal offspring which enhances the survival rate of the newly born species.  

Genetic variation causes genetic evolution which lead to development of individuals that are able enough to cope up with the existing environmental condition.  

Both over production and genetic variation are leading to  higher rate of survival of a newly borne individual and hence causes higher reproductive success.

Option B is correct

before, trains worked using the steam engine. thus, it uses heat so it is crucial to apply heat balance. the steam engine absorbs energy during the stage of boiling water. so, this is the endothermic reaction. when the steam is used to work the piston, it has to release this energy through running the train. the excess energy is released as an exhaust to the chimney. this is the exothermic process because it releases energy to the surroundings.