Aprotein channel is a transport protein that a. always moves substances against a concentration gradient. b. pumps ions out of a cell. c. serves as a tunnel for specific substances. d. always requires energy from the cell.

Rank the three variables in terms of how strongly they affect the "species" composition of the bacterial communities. place the variable with the weakest effect on the left and the variable with the strongest effect on the right.

On a recent expedition to a remote region of northern canada, scientists uncovered skeletal remains from about 100,000 years ago. surprisingly, all the skeletal remains, which included many species from differing biological families and spanned about two thousand years, showed evidence of experiencing temperatures in excess of 1000 degrees fahrenheit (or 538 degrees celsius). which of the following, if true, best explains the apparent paradox between the cold environment and the evidence of the bones experiencing hot temperatures? (a) chemical changes that naturally occur during the process of decay in only one north canadian species produce the same evidence of the species' skeletons being exposed to hot temperatures as the expedition scientists found. (b) a little over 103,000 years ago, a large fire is known to have occurred in northern canada. (c) strong evidence exists that as early as 70,000 years ago, homo sapiens around the world relied heavily on fire to cook animals. (d) in the same expedition and in roughly the same layer of excavation, scientists found rudimentary wood cutting and hunting tools used by early humans.

What would most likely happen if a person increased the amount of saturated fat in his or her diet? the person's risk of cardiovascular disease would increase. the person's risk of cardiovascular disease would decrease. the person's bad cholesterol would decrease. the person’s good cholesterol would increase.