Select the correct statement about complement. a. complement can be activated through three pathways: classical, secondary, and alternate. b. complement proteins c1 through c9 act exclusively in the classical pathway. c. an adaptive immune mechanism is often involved in directing complement to its target. d. the membrane attack complex consists of complement proteins c3a through c5.

C

Explanation:

A is wrong as 3 pathways are: classical, lectin, alternative

B is wrong - many C1-C9 act in other 2 ways EX C5

D is wrong - MAC consists of C5-C9

answer; i believe the correct answer is (sporophyte);

4.) metal

"-the movement of carbon from the nonliving environment into living things and back to the environment

-carbon is the essential component of proteins, fats, and carbohydrates (which make up all organisms)

-carbon exists in air, water, and living organisms

-producers convert carbon dioxide in the atmosphere into carbohydrates during photosynthesis

-bacteria in the atmosphere cycles through the system in filtration units

-in cellular respiration, carbon is released back into the atmosphere as carbon dioxide

-some carbon is stored in limestone (forming one of the largest "carbon sinks" on earth)

-largest carbon reservoir on earth= limestone

-carbon stored in the bodies of organisms as fat, oils, or other molecules may be released into the soil or air when the organism dies

-this may form deposits of coal, oil, or natural gas (fossil fuels, which increased the atmospheric carbon dioxide)

-fossil fuels store carbon left over from bodies of organisms that died millions of years ago

-they are located in the surface of earth, deep within the earth and beneath the ocean floor."