If the fossil of a seashell is found buried in a desert region, what might you learn from that fossil? A. Early humans used shells in the desert.
B. Dinosaurs probably lived in the region.
C. An animal that eats animals in shells must have moved it there.
D. The area was once covered by water.

Explain how paleontologists use trilobite fossils as index fossils for various geologic time periods.

Which process is represented a.) deletion b.) nondisjunction c.) translocation d.) insertion

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