Which scientist determined that the farther a planet is from the sun, the longer it takes to orbit the sun? Copernicus

Halley

Doppler

Kepler

How can you keep track of variables in a science experiment?

In the water cycle , when does water undergo a chemical change

Photosynthesis uses co2 and cellular respiration produces co2. we call the point when the two processes are in balance--when there is no net production of co2--the compensation point. how might you limit one of the processes in order to achieve a compensation point?