What evidence has allowed scientists to conclude that the common ancestor of modern chimps
and humans lived around 7 million years ago?
a. Stone tool usage began showing up in the human lineage around 7 million years ago, and
chimps do not use stone tools.
b. From the changes scientists have observed in chimps over the past 200 years, they predict it
will take at least 7 million years for today’s chimps to evolve into more humans.
c. Biological molecules such as proteins and DNA reveal differences between humans and
chimps that would have taken around 7 million years to accumulate.
d. Scientists know from whale evolution that it takes around 3.5 million years for brain size to
double in volume in a species’ lineage, and chimp brains are 300 cubic centimeters, while
human brains are around 1,300 cubic centimeters.

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.

2points what do bacteria have in common with the cells of other living organisms?

Which type of neuron stimulates muscles to contract?