Tem cells are undifferentiated cells that have the ability to continue to grow and divide in their nonspecialized state for long periods of time (e. g., months or years).

although the genes found within stem cells are the same, stem cells differentiate into unique cell types (e. g., muscle cells, nerve cells, etc.) due to

a)mutations in their genetic code.
b)different patterns in their gene expression.
c)meiotic division and fertilization.
d)random segregation and proliferation.

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.

All but one describes an effect of aging on the digestive system. a) decreased acid secretion b) decreased elasticity of stomach c) capacity to resist damage decreases d) food remains in stomach for less time

Multicellular organisms use cell division, mitosis, for growth and the maintenance and repair of cells and tissues. single-celled organisms may use cell division as their method of reproduction. regardless of the reason for mitosis, the process ensures genetic continuity. what is the step in the cell cycle that ensure genetic continuity?