Animals were used for food.!
Answer:
H20 is not a product of combustion
A.) Veins in the pulmonary circuit carry oxygen-rich blood
red blood cells are used to circulate oxygen through out the body, thus it is true.
reproduction, heredity, variation in fitness or organisms, variation in individual characters among members of the population.
A gateway substance is something that may be menial but could lead to something bigger, an example is weed in the drugs world, weed is not hard to get and is usually a gateway drug to stronger types of drugs and potentially more dangerous
