Which of these organisms are most likely to occupy similar niches in different ecosystem A. Oak tree and maple tree
B. Kangaroo rat and kangaroo
C. Earthworm and freshwater eel
D. Koala and black bear

What is the average speed of a car that traveled 300.0 miles in 5.5 hours

What blood vessels carry blood to the heart? away from the heart?

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.