In studies about new medicines, researchers usually give one group of patients the medicine that is designed to treat an illness. they give another group of patients a placebo, which is taken the same way as the medicine but does not actually contain the ingredients of any medicine. different medicines are tested in different experiments, but the placebos usually contain the same non-medical ingredients. if both groups of patients are healed, then researchers cannot be sure whether the medicine caused improvement, but if the group given the medicine is healed while the group given the placebo remains ill, researchers can conclude that the medicine causes the illness to go away.

in medical experiments, which group receives placebos?

the experimental group
the control group
both the experimental and control groups
neither the experimental nor control group

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.

An animal cell (left) and a plant cell (right) are shown. which organelle, labeled x in the diagram, is found in both plant and animal cells?

Explain what a zygote is. use the terms egg cell, sperm cell, and fertilization in your explanation.