Which of the following is most likely a characteristic of a person with a weakened immune system?

A. T cells are very active in fighting infections.
B. The body replaces T cells as quickly as those cells die.
C. Opportunistic infections make the person very sick.
D. White blood cells produce many antibodies.

Starting at the smallest, most simple level and working your way up to the most complex, explain how the following terms are connected. note-these terms are not in order molecules, atoms, organism, tissues, cells, organ systems, organs

Which of the following factors would not contribute to allopatric speciation? a) a population becomes geographically isolated from the parent population. b) the separated population is small, and genetic drift occurs. c) the isolated population is exposed to different selection pressures than the ancestral population. d) different mutations begin to distinguish the gene pools of the separated populations. e) gene flow between the two populations is extensive.

Which of the following terms would bb represent in an organism? a. phenotype b. genotype c. genetics