Apoint mutation that changes a uac codon into a uag codon is a mutation.

nonsense mutation

Explanation:

A point mutation is a mutation within DNA sequence when a single nucleotide is changed (substitued, deleted, added). They can have various effects depending on the type of point mutation. For example, nonsense mutations are point mutations that result in a premature stop codon. UAC codon codes for the tyrosine amino acid, while UAG is stop codon. A s a consequence, protein product is usually unfunctional because it is incomplete.

Nonsense mutations can cause genetic disorders (e.g. thalassemia).

answer:

convection currents in the magma drive plate tectonics. heat generated from the radioactive decay of elements deep in the interior of the earth creates magma (molten rock) in the aesthenosphere. the aesthenosphere (70 ~ 250 km) is part of the mantle, the middle sphere of the earth that extends to 2900 km.