Seasonal conditions influence the life cycle of marine organisms. many animals that inhabit lakes have a reproductive process that occurs during the spring. which best explains why this is beneficial?
during this time the temperatures are low at the bottom of the lake where the processes take place.
the metabolism of animals is slowest at this time so their demands for food are low.
during this time the oxygen levels are higher at the top of the lake where the processes take place.
the cycling of water during this time produces consistent temperatures at each depth.

Option D,   The cycling of water during this time produces consistent temperatures at each depth.

Explanation:

Seasonal changes have a deep impact on the breeding pattern of animals. There are several lake animals which have short gestation period and hence prefer to breed during the summer and spring season.  

During spring season the temperature is comparatively warmer and sunlight is available for a longer period of time. Due to which water cycling with in the lake produces a constant range of temperature throughout the lake at all depths. With higher temperature the productivity all organism be it plant or animal increases

Hence, option D is correct

answer: - b cells

explanation: -

so, the b cells mediate their action by identifying the antigens present on the surface of the pathogens and then producing antibodies in return to mediate its effect.