Question

a mutation always causes a mutant phenotype - i.e. an observable change in the organism.
true
false

Explanation:

Mutations can be silent. For example, in some cases, a change in the DNA sequence (mutation) may not lead to a change in the amino - acid sequence of the protein (due to the degeneracy of the genetic code). When there is no change in the protein, there may be no observable change (mutant phenotype) in the organism.

Answer:

FALSE