Regular physical activity can help prevent or manage many health conditions including high blood pressure, diabetes, depression, Osteoporosis, and Obesity. Im not sure if its your text book answer but i am a personal trainer and i gave you more than one benefit to choose from. Physical activity should be a way of life for everyone
Seymour Benzer used phage T4 mutants, Experimental
evidence that a gene is a linear sequence of nucleotide pairs. Some regions of
chromosomes have "hot spots" for mutations. Benzer's experimental
approach to fine structure mapping of the rII locus. Generated 1612 spontaneous point mutations
and several deletions in rII locus identified two complementation groups, rIIA
and rIIB. Mapped locations of deletions
relative to each other using recombination.
Mapped locations of point mutations relative to the deletions. Tested
for recombination between all point mutations within the same complementation
group.
The answer is D, white blood cells.
The main function of white blood cells is to defense the body from bacteria or other pathogens. There's 2 main kinds of white blood cells, lymphocytes and phagocytes. Lymphocytes mainly produce antibodies that can kill bacteria or any pathogens, and phagocytes can ingest the pathogens directly.
Therefore, since the white blood cells can protect our body, they're part of our immune system.