Which of the following is observed in a clinical trial?

Which statement is true about the cell theory? a) it is well-supported by evidence. b) it is unchangeable and permanent.

Freckles are a dominant trait in humans. both of the girls have the genotype ff for freckles. if either one marries a man with no freckles, what are the chances that their children will have freckles?

Which organ controls breathing? lungs alveoli heart diaphragm