Claim: Vegetable and animal fats are similar compounds with different melting points related to the presence of carbon-carbon double bonds (product of the addition of hydrogen to the unsaturated bonds) in the fatty acids components.
Evidence: Vegetable and animal fats are similar compounds with different melting points. The melting points are related to the presence of carbon-carbon double bonds in the fatty acids components. The addition of hydrogen to the unsaturated bonds (alkenic double C=C bonds) results in saturated C-C bonds, effectively increasing the melting point of the oil and thus "hardening" it.