Which of the following is a key abiotic factor for aquatic ecosystems but not for terrestrial ecosystems?
(A) Light
(B) Nutrients
(C) Salinity
(D) Temperature

A60-tooth gear is connected to a 72-tooth gear. if the smaller gear turns 12 times, how many turns does the larger gear make?

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.

Some substances but not other can cross the (blank) membrane of a cell