HIV predominantly infects T-helper cells, cells that are responsible for coordinating B- and T-cell activity. Based on this information, explain why HIV-infected individuals are at a very high risk for developing microbial infections. List the causative agent (virus) and discuss its properties. Name and briefly discuss 3 diseases that AIDS patients are more likely to contract.

Even though the ostrich is a flightless bird, ostriches still possess wings that stretch approximately two meters across when fully extended. scientists speculate that when dinosaurs became extinct, some of the birds that lived during that time became land dwellers since they were able to consume the food that the dinosaurs once ate. over time, these species grew larger and heavier. eventually, the ostrich species became too big to fly. the wings found on ostriches are known as a. analogous structures. b. homologous structures. c. vestigial structures. d. symmetrical structures.