Which is a reason for the rise of nitrate levels in ground water?
a) overuse of fertilizers
b) ammonification by animals
c) soil erosion at grasslands
d) nitrogen fixation by azotobacter

What evidence did mendel find that supported his law of independent assortment? a. dominant traits are expressed when there is a dominant allele. b. traits do not affect the inheritance of other traits. c. some traits have three or four different alleles. d. plants and animals can both reproduce sexually.

The circles, or orbits, for electrons are called energy levels. each level can hold only a certain number of electrons. add electrons to each level until you can't add any more. how many electrons can each level hold?

Darrel conducted an experiment with the following procedure: fill two cups with ice water. place an uninflated balloon snuggly onto your left index finger. blow a little air into an identical balloon, and place it onto your right index finger. place both fingers into the cups of ice water. darrel noticed that his right finger felt warmer in the ice water than did his left finger. which of the following does the experiment show? a. air is a good radiator of heat. b. air is a good insulator of heat. c. air is a good conductor of heat. d. air is a good convector of heat.