The troposphere contains 90% of the ozone in the atmosphere. Please select the best answer from the choices provided
T
h
F

Which system revise and send electrical signals throughout the body

Did you know that a blue wales tongue weighs more than an elephant?

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.