Which of the 4 types of macromolecules (carbohydrates, lipids, proteins or nucleic acids) are receptors?

Did you know that a single bee would have to go to over 2 million flowers to make a single pound of honey?

Some substances but not other can cross the (blank) membrane of a cell

Fossils of ancestors of the modern horses show a small 4-toed almost dog-like browsing animal named eohippus over time the horses got larger lost toes and changed to a grazing diet what is the best explanation of why this change occurred