HELP! Solar, biomass, geothermal, wind, and hydropower energy are all renewable sources of energy. They are called renewable because they: a. Are clean and free to use

b. Can be converted directly into heat and electricity

c. Can be replenished by nature in a short period of time

d. Do not produce air pollution

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.

Hemoglobin is a proton that carries oxygen around the body what is hemoglobin made from

How dose plate tectonics effect climate