Individuals with hiv sometimes contract secondary infections that are rare in the rest of the population. this is because people with hiv a. are unable to fight off these secondary disease-causing organisms. b. are more frequently exposed to these secondary disease-causing organisms. c. release hormones that attract the secondary disease-causing organisms. d. release substances that increase the strength of the secondary disease-causing organisms.

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.