The amount of one substance in a certain volume of another substance is its a. concentration. b. coagulation. c. filtration. d. irrigation.

Astudent observes a star from two positions of earth in its orbit, in summer and winter, and measures the change in the position of the star. which of these can be best calculated by this method?

Plants consume most of their carbon from a. the soil b. the water c. the roots d. the air

Most of the carbon on earth is stored in the form of