The filters blood by using phagocytic cells. A. thymus
B. spleen
C. tonsils
D. lymph nodes

Based on the results of this study, what questions remain unanswered? how can these questions guide future research

What would be the result if crossing over did not happen during meiosis in humans? a. there would be less genetic variation in humans. b. parents would be more likely to look like their children. c. the human population could not reproduce. d. children would have more chromosomes.

Where do the respiratory and circulatory systems meet? a. in the heart b. in the muscles c. in the lungs d. in the brain