The role birds play in ecosystems include
A. Provide nitrogen compounds to the environment
B. Both A and B
C. Being predators and prey.
D. Transplanting mollusks to freshwater habitats

Which of the following are not matched correctly? cd8+: directly destroy infected or cancerous cells t reg cell: reduce the adaptive response once threat passes t l: activate cellular branch (cytotoxic t cells, macrophages, nk cells) t 2: stimulate b cells to make antibodies t (cd4+): mhc i