The more numbers of the homologous structure, the more likely they have recently shared a common ancestor.
Explanation:
Homologous organs are defined as those organs which do have different functions but a similar basic structure which denotes the divergent evolution. Homologous organs are seen in species that are very close to each other which are more related with each other in terms of evolution. For example, a bird is more close to each man than a fish, so do share more homologous organs common to man than fishes do. Examples of the homologous organs are hands of human and wings of birds. They have same basic structure like skeletal structure which is humerus, radius, ulna, carpals, metacarpals and phalanges. They are similar in structure but have different functions like flying in birds and gathering food in humans.
Valves ensure blood flows toward your heart. Vein valves work to bring the blood that flowed down via arteries back up to your heart.
Answer:
b. They are produced by memory B cells
Explanation:
The rapid cell division in activated B cells is followed by the differentiation of daughter cells into the plasma cells. The plasma cells are the precursor for antibodies and memory B cells. The antibodies kill the antigens while memory B cells are long-lived cells.
Hence, antibodies are not produced by memory B cells but by plasma cells.
