Which of the following are independent variables?
A scientists measure how tall a plant grows
after feeding it fertilizer
The amount of dog food given to puppies is
decreased by a vet to see if they will lose
weight.
A scientist changes the amount of sunlight a
plant receives in an experiment to see how
they grow in different levels of light
The vet measures the weight of the puppies
after one week.

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.