Answer:
embryonic development
Explanation:
other non aquatic vertebrates exhibit gill slits even though they never breathe through gills. These slits are found in the embryos of all vertebrates because they share as common ancestors the fish in which these structures first evolved.
A good reason for why tobacco smoke is considered a carcinogen is because it causes mutations leading to cancer.
Answer:
No change occurs in phenotype.
Explanation:
This can happen in many situations:
perhaps the mutation occurs in a stretch of DNA with no function, or perhaps the mutation occurs in a protein-coding region, but ends up not affecting the amino acid sequence of the protein.
