Interaction between molecules that causes a chemical change, converting an existing substance into a new substance

Which traits do human embryos have that link them to a common ancestor with fish and reptiles? a. scales and tail b. gill slits and scales c. tail and gill slits d. hair and tail

If blood contains 150g of hemoglobin per liter of blood, how much hemoglobin would be contained in 10 ml of blood

The polymer used for the nonstick surface of cooking utensils is 24.0%c and 76%f by mass. what is the empirical formula of this polymer?