In an experiment to determine the effect of exercise on pulse rate, a student checks his pulse rate before
and after exercising for several minutes. the purpose of checking his pulse rate before exercising is that it
(1) serves as the conclusion for the experiment
(2) is needed to justify the sample size
(3) serves as a control for the experiment
(4) is needed to formulate a hypothesis

Which would be the outcome in a fertilized egg if the process of meiosis did not occur? twice as many chromosomes as the parents half as many chromosomes as the parents same number of chromosomes as the parents triple the number of chromosomes as the parents?

The phlogiston theory in the 17th century attempted to explain burning. the theory stated that combustable objects contained a material called phlogiston, a substance without mass, color, odor, etc. after objects burned, the objects were dephlogistonated and were then in their true form. the phlogiston theory was accepted until the 18th century, when lavoisier proved that combustion requires a gas that has mass. phlogiston is considered a) to be scientific knowledge b) not to be scientific knowledge c) to be proven by scientific method d) to be accepted in the modern scientific community

Which genetic disorders, caused by an extra x chromosome (xxy), is characterized by a lack of testicular development in males, effeminate features, possible mental impairment, and a thin stature?