Please hurry Theo was doing research to support the claim that
exercise increases heart and lung health. He had 50
people do a rigorous exercise program. Each week, for
six months, he tested their heart and respiratory rate. He
determined that exercise does increase heart and lung
health.

Which best describes his claim?

A-It is valid because he used multiple trials.

B-It is invalid because he did not have a control group

C-It is invalid because his sample size was small.

D- It is valid because he controlled the exercise
program.