Answer:
A. single-gene
Explanation:
It is controlled by a single gene that has two alleles. The allele for a widow's peak is dominant over the allele for a hairline with no peak.
Answer:
b.nuclear energy to heat energy to electrical energy
<span>Metamorphic rocks form by existing rocks join together under high heat and pressure. Examples of metamorphic rocks are marble, schist, slate, and quartzite. Metamorphic rocks formed when the minerals are chemically changed due to heat and pressure. They are often seen near magma but they do not melt like igneous rock.</span>