PLEASE HELP ASAP

A specific immune response begins when a white blood cell comes in contact with an antigen (any substance that the immune system does not recognize as part of the body). What external factor typically triggers a specific immune response?

A. an invasion of a microorganism from the external environment
B. a fluctuation of the external air pressure
C. a large release of adrenalin by the endocrine system
D. a change in the external temperature

Where are the strongest jet streams located?

An organism's reproductive strategy includes all of the following except a. the number of offspring produced. b. the amount of energy expended in producing offspring. c. the length of time parental care is given d. the number of alleles an organism passes on.

Why are carbon dioxide concentrations expected to increase? a carbon dioxide concentrations are expected to increase, because fossil fuel burning is expected to increase b. carbon dioxide concentrations are expected to increase, because of an increase in agriculture. c.carbon dioxide concentrations are expected to increase, because more land will have to be cleared for increasing populations and agricultural use. d. all of the above select the best answer from the choices provided mark this and return save and exit next submit submit