What was the most important development in the biological and medical sciences in the late 19th and 20th centuries based on the work of roy porter and ernst mayr?

In many humans, exposing the skin to sunlight over prolonged periods of time results in the production of more pigment by the skin cells (tanning). this change in skin color provides evidence that -

The wind is to parities grasses because it them

Veronica and her little sister, monique, are playing on a seesaw. if veronica weighs 75 pounds, and monique weighs 60 pounds, which statement is true?