First- b
second - d
third - c
fourth - a
B. They become extinct
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Answer:
Mutations can create entirely new alleles in a population which changes the allele frequencies of a gene pool.
Answer/Explanation:
<h3>Incomplete dominance</h3>
In incomplete dominance, one allele is not entirely dominant over the other, so heterozygotes (organisms with two different alleles for the gene) show an intermediate or blended phenotype.
For example, consider flower colour.
- If the allele for red flowers (R) was dominant over the allele for white flowers (r), then there are three possible genotypes (RR, Rr, and rr) and two possible phenotypes. (Red (RR and Rr) and white (rr)).
- However, if the allele for red flowers (R) was incompletely dominant over the allele for white flowers (r), then there are three possible genotypes (RR, Rr, rr), and three possible phenotypes (red (RR), white (rr), and pink (Rr))
<h3>Co-dominance</h3>
In incomplete dominance, two alleles are both expressed, one is not dominant over the other. Therefore, heterozygotes (organisms with two different alleles for the gene) express both traits.
For example, consider flower patterns.
- If the allele for spots (F) was dominant over the allele for stripes (f), then there are three possible genotypes (FF, Ff, and ff) and two possible phenotypes. (Spots (Ff and ff) and stripes (ff)).
- However, if the allele for spots (F) was co-dominant to the allele for stripes (f), then there are three possible genotypes (FF, Ff, ff), and three possible phenotypes (spots (FF), stripes (ff), and spots and stripes (Ff))
