The 100 members of an extracurricular club at a nearby college are subdivided into 6 groups based on ethnic identification. Since 40% of the club is Caucasian, the researcher ensures that 40% of his sample is also Caucasian. The researcher is using
sampling.
A. cluster
B. stratified
C. random
D. systematic

The human eye contains a molecule called 11-cis-retinal that changes shape when struck with light of sufficient energy. the change in shape triggers a series of events that results in an electrical signal being sent to the brain that results in vision. the minimum energy required to change the conformation of 11-cis-retinal within the eye is about 164 kj/mol.

Light waves can move through , but they travel fastest when they move through a(n) .

About 3% of the water on earth is freshest. only about 40% of that freshwater is available for human use. why is so much freshwater unavailable for human use?