Answer:
option a
Explanation:
because When hydrogen is used to power a fuel cell, the only byproducts are water and heat—no pollutants or greenhouse gases are produced.
The central element for all living things is carbon, which is why you might often hear the phrase "carbon-based" lifeforms. Another term is often "organic matter"
A trait is the organism's feature. So, a trait would be eye color. A phenotype would be hazel. An allele is a gene. It can be recessive or dominant.
