D.The infrastructure for using oil is already in place and there are costs associated with changing the energy infrastructure.
Explanation:
Non renewable energy sources are available in limited amount and should be used in a sustainable way. However, switching from one energy source to another needs cost intensive changes in the infrastructure. Hence, continuing the use of non-renewable energy source is recommended despite its limited supply and harmful effects on the environment.
For every trait, there are two types of characters - dominant and recessive which are determined by the combination of the alleles for a given gene.
Each gene has 2 types of alleles- one is the dominant allele which always expresses itself that is in both homozygous and heterozygous conditions whereas the other one is the recessive allele which can only express itself in the homozygous conditions.
In Mendel's experiments when he crossed plants with different traits he observed that in the F1 generation there was always a single trait that was getting expressed and it was the trait that was being coded by the dominant allele.
