Answer - Theory
Reasoning - Your best bet and term to describe the evolution by natural selection is theory as to still scientific theory/research is still ongoing and changes can be made in a different direction.
Answer:
<u>3) Uncontrolled cell division occurred as a result of gene mutations</u>
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Explanation:
Spontaneous modifications within the genome may occur during the process of cell division. When copies of the DNA inside the cell are made, these mutations cause errors; and can include small single nucleotide polymorphisms, and large scale additions or deletions across multiple genes.
Some, like somatic mutations, exist only inside vegetative (body) cells, that cannot be passed onto offspring. This is caused by several factors like
- UV radiation,
- chemical mutagens,
- infective agents
UV radiation damages strands of DNA, by causing dimers to form; here, consecutive nucleotide bases covalently bond instead of those on the complementary strand. This conformational change causes errors in DNA proofreading and repair mechanisms where bases are not well-incorporated into the strand- tumors (clumps of uncontrolled cell growth) may form, resulting in melanoma, a type of skin cancer.
TRUE. A true-breeding organism, sometimes also called a purebred, is an organism that always passes down certain phenotypic traits to its offspring.