Which of the following will allow nitrogen fixation to occur?

A: photosynthesis

B: decay

C: bacteria

D: conversion of hydrogen

The molecular clock has limited usefulness for estimating divergence times among species in part due to the saturation of DNA sequences. This occurs because A. DNA sequences are unable to revert back to previous allelic states. B.

Why do scientists think that introns and exons contribute to evolutionary flexibility?

How are arteries and veins alike?

List three basic activities of living things?

How many senses do snail have? What are they

What is the term for brief episodes of neurologic deficit caused by temporary interference with blood supply to the brain?

Which of these celestial bodies has a tail? a-asteroid b-comet c-moon d-planet

What is the function of myeloma cells used in the production of monoclonal antibodies?

Describe a simple nervous system. Give an example of an organism that has a simple nervous system.

An example of a parallel choice on a dichotomous key is