Mutation can be defined as a phenomenon due to which the nucleotide (DNA or deoxyribonucleotide) sequence present in the genome of an organism gets altered.
Mutation can occur because of various factors like error-prone replication (DNA polymerase fails to proofread and incorporate the correct nucleotide in the daughter strand), improper DNA repair, exposure to mutagens (that causes mutations like Ultraviolet rays or UV rays that causes the formation of thymine dimer in the DNA), exposure to mobile genetic components like Transposons.
The different types of mutations with respect to their effect on the DNA sequence are:
Indel mutations: Also called Insertion Deletion Mutations where large sequences of DNA are either incorporated or removed from the genome. If such a mutation occurs in the protein coding region of a gene, then no functional protein can be obtained from such a gene.
Base substitution: Here the required nucleotide in the DNA sequence is replaced with some other nucleotide during the process of replication. If this happens in the wobble nucleotide of a codon (the last nucleotide in the triplet codon. A Codon is responsible for encoding for an amino acid. Due to degeneracy of the genetic code, multiple codons can encode for a particular amino acid), that would not affect the protein sequence but if it happens in the other two nucleotide of the codon it can cause change in the amino acid sequence of the protein, resulting in a non-functional protein.
Silent Mutation: Where the mutation has occurred either in the non-protein coding region of a gene or in the wobble nucleotide of a codon such the amino acid sequence does not get altered.
Non-sense Mutation: Where the mutation is such that a stop codon is introduced in the middle of the protein coding region of a gene. Hence, a truncated non-functional protein can be produced from such a gene.
Answer: I think that it would be C because blooms are due to eutrophication, which means that there are high levels of phosphate in the water. Phosphate is a main ingredient in pesticides, which can run-off into rivers.
