Cystic fibrosis is a disease that
a. causes all those infected to live only into their teen years
b. makes it difficult to breathe
c. can be cured with proper medication
d. occurs most frequently in people of asian descent

Approximately what wavelength of light is best absorbed by chlorophyll a

Which of the following best describes the purpose of the parathyroid hormone? a. it decreases the blood calcium level and decreases blood phosphorus level. b. it decreases the blood calcium level and increases the blood phosphorus level. c. it increases the blood calcium level and increases blood phosphorus level. d. it increases the blood calcium level and decreases blood phosphorus level.

Where is having brightly colored feathers that attract mates most clearly an adaptation for a bird? a. a forest with dense vegetation b. a sandy beach beside an ocean c. a snowy tundra with little vegetation d. a swamp with many hawks that eat birds