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. I
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

answer: carbon 14 can only be used to determine the age of the organisms that were once living, and igneous rocks are non living.

explanation:

carbon 14 dating is used to determine the age of the sample by estimating the amount of carbon 14 present in the sample and then comparing it with a reference standard.carbon 14 is a isotope of carbon which is radioactive and unstable. carbon 14 is assimilated by all plants and animals throughout their life from carbon dioxide. however, one the organisms die they stop this assimilation and the carbon 14 content starts to decrease.by knowing how much of carbon 14 is left in an organism after his death, one can estimate the age of the organism. the materials whose age can be estimated by carbon 14 method are the organic compounds. however, some inorganic compounds such as aragonite   shell can also be dated.however, if we consider the igneous rocks it is a non living component which never accumulated carbon 14 in it and thus, we cannot use carbon 14 dating method to estimate its age.

Telophase colchicine is a chemical obtained from plants that prevents the assembly of spindle fibers

Ibelieve the answer is d: quarterany