The curve on the left shows the height of a rat population in 2007. the curve on the right shows the population in 2010. what type of selective pressure was taking place in this population?

Natural selection took place, causing that rats that were too small to survive in the environment to die off. This means the rats’ genes changed causing their average height to grow to better suit their environment.

i think a) betsy can donate only blood to mark is correct because, mark and betsy have the same blood type. whereas nobody else has b+ blood so betsy can't donate to them.

is this a psat question, if so do not cheat try your best.