The mixing that occurs at the fall and spring turnover replenishes nutrients in the upper layer of water in a stratified lake (epilimnion) and increases the level of oxygen in the lower layer of water in a stratified lake (hypolimnion).
Answer:
Villi, alveoli and nephrons are similar as :-
B. They provide large surface areas for molecular exchange.
After the macrophage fails the Helper T Cell stimulates the B cells (create antibodies) if pathogen is extracellular and Cytotoxic T Cells (killer T cells, release perforin) if pathogen is intracellular. Once the pathogen is killed the B Cells create Memory B Cells and the Killer T Cells create memory T Cells.
<span>Hope that's helpful.</span>
