Scientists have noticed that during a certain phase of cell division, the two halves of a normal, dividing cell look and act like two cells migrating (or moving) away from each other. The concentration of a chemical called PIP3 is low at the cleavage furrow, or the 'backs' of what will be two new cells. PIP3 concentration is high on the sides that represent the 'fronts' of what will be two new cells. Substances called CDK's control the breakdown of the nuclear membrane during mitosis. If the genes coding for these substances are mutated, mitosis can run out of control and cells will not stop dividing. Which specific phase in the cell cycle is regulated by CDK's?

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.

2. which of the following statements does not accurately describe stem cells? a. embryonic stem cells make up the inner cell mass of a blastocyst. b. with more research, stem cells may be used to repair or replace damaged cells. c. the use of stem cells is without any objections since it can be used in therapies to humans. d. adult stem cells are multipotent and can differentiate into many types of cells.

As water is cooled from 4 to 0, its density