3: B Nervous system. 4: A Sensing and responding to its external environment.
The correct answer is microglia.
<span>Microglia is glial cells found in the central nervous system with the protective role. Because they are the resident macrophage cells, they act as the first and main form of active immune defense. Microglia is constantly cleaning the CNS for plaques, damaged or unnecessary neurons, and infectious agents, like viruses or other microorganisms.</span>
It is found in the cell walls of plants.
For the generalized scheme of Alternation of generations (see p. 120), plants have two forms based on a genetic complement that are the Sporophytes (2N diploid) and Gametophyte (N haploid). The processes connecting the two stages are gametangia producing haploid spores and zygote cell growth producing haploid gametophyte. Group of answer choices
