Answer:
O H20 and CH4, but not O2
Explanation:
Compounds consist of multiple elements. O2 is just two oxygen atoms, meaning two atoms from the same element.
Since the trait is dominant, it is possible for his parents to be heterozygous (Bb). So they have the trait but they have a gene they can pass on with out it. If both of his parents Bb then he could’ve gotten both recessive and therefore not receive the trait
B. They decrease. As more we use the sources of nature, the less is left.
Its called a microscope slide