Which level of organization is formed when a group of organs work together to perform complex functions?

a) molecule

b) organ

c) organ system

d) tissue

An equinox occurs when a. neither end of earth's axis is tilted toward or away from the sun. b. the north end of earth's axis is tilted away from the sun. c. the north end of earth's axis is tilted toward the sun. d. earth's axis is parallel to the sun's rays. select the best answer from the choices provided a b c d

An isotope undergoes radioactive decay by emitting radiation that has a –1 charge. what other characteristic does the radiation have?

What causes the development of most clouds and precipitation in the atmosphere?