As the trait is dominant and controlled by a single gene, the mutation must have occurred on both diploid copies, true or false?? with reason please

True.

Explanation:

Diploid copies are cells generated as copies of other cells and which have two homologous copies, exactly the same, of the cell that gave rise to it (the mother cell). In this case, if the mother cell has a mutation that causes a dominant characteristic and controlled by a single gene, it means that its diploid copies will have that same mutation, since they are exact copies.

label a cell membrane

label b cytoplasm

label c ribosomes

label d dna

the membrane forms the outside of the cell

cytoplasm is the liquid within

ribosomes are the components within that distribute rna

the dna is the genetic make-up