Which by-product of photosynthesis was important in altering the atmosphere of the earth so that aerobic organisms could evolve?

What is a traditional chinese touch therapy involving finger pressure applied to specific areas of the body to restore the flow of qi.

Which scientific design has both practical limitations and limitations due to scale? studying the effect of bleach on the growth of mold spores exposing cultures of duckweed to different intensities of light observing the replication of dna molecules with a hand lens using colored marbles to model a cross between two colors of rabbits

Adding more tributaries to a local river basin can have what effect?