The body needs vitamin D in order to use calcium. An experiment is designed to study the effects of calcium and vitamin D supplements on the bones of first-year college students. The outcome measure is the total body bone mineral content (TBBMC), a measure of bone health. Three doses of calcium will be used: 0, 300, and 600 milligrams per day (mg/day). The doses of vitamin D will be 0 and 150 international units (IU) per day. The calcium and vitamin D will be given in a single tablet. All tablets, including those with no calcium and no vitamin D, will look identical. Subjects for the study will be 30 men and 30 women.

There are _____ factors. Answer choices: (one / two / three / four)

There are ______ treatments in this design. Answer choices: ( one / two/ three/ four / five/ six)