How do the nucleotides in dna bond with each other within a strand?

How do ecosystem respond to nature disasters such as fires and floods

Why is it important that fibrin is insoluble in water?

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