Answer:
Density is a measurement that compares the amount of matter an object has to its volume. An object with much matter in a certain volume has high density.
Explanation:
I would go with B. Not everyone can learn this skill.
Hydrogen ion, strictly, the nucleus of a hydrogen atom separated from its accompanying electron. The hydrogen nucleus is made up of a particle carrying a unit positive electric charge, called a proton. The isolated hydrogen ion, represented by the symbol H+, is therefore customarily used to represent a proton.
Answer: The answer would be minerals. Synthetics are made by men, and shouldn't be found in the earth Vitamins are organic Cement is a mixture of an organic compounds and rarely found in nature.
