A researcher identified 100 men over forty who were not exercising and another 100 men over forty with similar medical histories who were exercising regularly. She followed all the men for several years to see if there was any difference between the two groups in the rate of heart attacks. This is a(n) … 

The atomic number of an atom or element is: 

A part of a chromosome that attaches sister chromatids to each other defines the term:

We wish to compare the average ages of the math and science teachers at your high school. Which is the best way to collect the data? 

Which bond is best described by Paula Abdul’s amazing song “Opposites Attract”?

Hoping to get information that would allow them to negotiate new rates with their advertisers, Natural Health magazine phoned a random sample of 600 subscribers. 64% of those polled said they use nutritional supplements. Which is true?I. The population of interest is the people who read this magazine.II. “64%” is not a statistic; it’s the parameter of interest.III. This sampling design should provide the company with a reasonably accurate estimate of the percentage of all subscribers who use supplements. 

The first energy shell of an atom contains a maximum of: 

The compound that enters the Kreb’s cycle is:

Hemophilia A is an X-linked recessive disorder. If a normal man marries a woman who is a carrier, what fraction of their sons will have hemophilia?

Meiotic cell division replicates a cell’s DNA _____ and then divides ______.