Malaria, a type of parasite, infects 500 million people each year by infecting the red bloodcells of its host. The virus, HIV, that causes AIDS, reports 50,000 newly infected persons. Which statement best differentiates the pathogens, parasites and viruses? A. All though both rely on other living organisms to survive, viruses are usually beneficial.

B. Although both rely on other living organisms to survive, parasites feed on the host organism.

C. Although both are living organisms, parasites depend on the cells of living things to reproduce.

D. Although both are living organisms, viruses break down dead plants and animals that other organisms use.

In a cladogram, what occurs at a node? a derived trait appears. evolution is stopped. an ancestor dies. the cladogram ends. aa as s as ss what are the chances that their offspring will have sickle cell anemia? 0% 25% 50% 100%

Which of the following statements is correct in hour our immune system responds to a potential pathogen? a. the adapted immune system will call on the innate immune system to destroy the pathogen. b. b cells will start reading the antigen code immediately and call t cells to assist in destroying the pathogen. c. the skin will be the first line of defense, and then the many phagocytes in the bloodstream will attempt to consume the possible pathogen. d. the t-cells in the adapted immune systems are the first to recognize the pathogen vaccines are weakened forms of disease causing microorganisms, which are given to patients to prevent disease. after the vaccine is administered, the immune system responds by creating a(n) to recognize the a. antigen, antibody b. antibody, antigen c. antibody, antibiotic d. antibiotic, antibody

Which of these outcomes is a negative impact of postindustrial societies on the environment? a. nomadic ways b. overpopulation c. overgrazing d. resource renewal