The main difference between ocean water and lake water is that ocean water contains - A: oxygen
B: salt
C: algae
D: plants

Which phrase is the best summary of the model shown? a. the transfer of the sun's energy through trophic levels b. a series of aerobic and anaerobic reactions c. a transformation of light energy into chemical energy d. the breakdown of food molecules

Connection compare and contrast genetic engineering to the process of natural selection. select all statements that are true.

The nervous system interacts with the endocrine system by a. using hormones as connections b. sending nerve impulses directly to glands c. using neuroendocrine cells as connections d. sending neurotransmitters directly to neurons