Multiple sclerosis (MS) is an autoimmune disease that strikes more often the farther people livefrom the equator. Could vitamin D—which most people get from the sun’s ultraviolet rays—be a factor? Researchers compared vitamin D levels in blood samples from 150 U. S. military personnel who have developed MS with blood samples of nearly 300 who have not. The samples were taken, on average, five years before the disease was diagnosed. Those with the highest blood vitamin D levels had a 62% lower risk of MS than those with the lowest levels. (The link was only in whites, not in blacks or Hispanics.)a)What kind of study was this?b)Is that an appropriate choice for investigating this problem? Explain. c)Who were the subjects?d)What were the variables?

The green colored pigment in chloroplasts is? a. nitrogen b. chlorophyll c. chlorophorm d. chlorofloromethane

Benito is doing research on the effects of florida's elevation on its climate. his notes include the following: 1. the average elevation of florida is 30 m above sea level. 2. the highest point in florida is britton hill, which is 105 m above sea level. 3. the change in temperature from 0 m to 1,000 m is 7 °c. what can benito conclude about the effects of florida's elevation on its climate? a.) florida typically experiences cold temperatures and temperature changes within a narrow range. b.) florida typically experiences cold temperatures and temperature changes within a broad range. c.) florida typically experiences warm temperatures and temperature changes within a narrow range. d.) florida typically experiences warm temperatures and temperature changes within a broad range.

The two tubes contain bromothymol blue. after 24 hours, what will the color of the water be in tube b? a. green (it won't change) b. yellow c. blue d. colorless (clear)