What is the key to maintaing water purrification services?

Which of the following is most important in making the typical seed more resistant to adverse conditions than the typical spore? a) a different type of sporopollenin b) an internal reservoir of liquid water c) integument(s) d) ability to be dispersed e) waxy cuticle

When lactate builds up in a runners muscles it causes a burning sensation what causes this to occur

In many humans, exposing the skin to sunlight over prolonged periods of time results in the production of more pigment by the skin cells (tanning). this change in skin color provides evidence that -