How does the digestive system convert food into nutrients and energy?

About how many years does it take for one cycle of surface water to become deep water and then surface water again in the oceans? 101001,000

Dna replication occurs in preparation for

According to the rna world hypothesis, rna acted as the genetic material and catalyzed reactions in ancient cells. what conclusion can you draw from this?               a.  this implies that dna and proteins aren't essential in cells today.    b.  this implies that rna can catalyze any chemical reaction that enzymes catalyze.    c.  this implies that if a cell has a problem with its dna, its rna can compensate for the damaged dna.    d.  this implies that dna and proteins evolved after rna.