The inside the stratosphere blocks ultraviolet radiation.

Chloroplasts and bacteria are in size. a. similar b. at different ends of the size range c. exactly the same d. none of these

Nephrons, the functional unit of kidneys, are responsible for formation of urine. the sentences describe situations that are the result of problems in the urine formation process. for the nephron shown below, match each situation to the step in the urine formation process where the problem lies.

Which kind of mutation has occurred when the codon for an amino acid is changed to a stop codon? a. a silent mutation b. a missense mutation c. a frameshift mutation d. a nonsense mutation