A changing climate has strong implications for biodiversity. Studies of fossil and pollen distribution show that species are very sensitive to climate changes. When the climate changes, species often die out in their present areas and colonize new areas. Therefore, as the climate changes in the future, there will be disruption of natural communities and extinction of populations and species.

Which of these environmental changes would most affect the arctic polar bears survival?

A)
drought

B)
an ice age

C)
deforestation

D)
global warming

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