Which of the following cannot undergo sexual reproduction? a) birds b) prokaryotes c) eukaryotes d) none of the above

Which statement about the immune system is false? a. lymphocytes reduce inflammation, b. b cells remember specific pathogens. c. most white blood cells kill bacteria d. white blood cells are made in lymph nodes.

The many stone tools, fragmentary animal bones, and teeth found at gran dolina, spain, indicate that hominids there? a. processed and consumed animals and other hominids. b. did not differ appreciably from earlier asian homo erectus. c. were similar to later homo sapiens. d. none of the above

Which line in the graph above best illustrates an effect of the carbon dioxide level in the blood on breathing rate before, during and after a period of exercise? 1.b,2.c,3.a,4.d