Which type of environment would tend to reduce genetic variation in a population because of evolution by natural selection? grasslands that are undergoing severe drought
an ocean ecosystem that is becoming more acidic
an old growth forest with trees that are over 1,500 years old
a tropical rainforest that is being deforested for farmland

Two students are working together on an experiment that measures the effect of different liquid fertilizers on the thickness of plants’ stems. which is most likely to result in the greatest amount of error in their scientific experiment? a.one student measures the plant stem widths by using calipers. the other student measures the widths of the same plant stems again by using a different pair of calipers. b.one student measures the plant stem widths by using calipers. the other student types the measurements as they are taken into a computer spreadsheet. c.one student weighs liquids for the experiment by using a calibrated scale. the other student weighs liquids for the experiment by using a different calibrated scale.

To test the responsiveness of the kidneys, scientists have designed an experiment tracking urine output of people during a normal day, while regulating the in-take of water by mouth. what would be an appropriate hypothesis for this experiment?

How many electrons can occupy any electron orbital?