Strands of DNA are tightly coiled in A. DNA
B. Base pairs
C. Chromosomes
D. Mitochondria

The greenhouse effect a. something that has occurred for millions of years b. an unnatural phenomenon caused by humans that maintains earths temperature range. c. the results of the differences in the angle of the suns rays d. an unnatural phenomenon that causes heat energy to be radiated back into the atmosphere

Which of th following is needed for cellular respiration to occur

What are the subsystem of the earth