Final answer:
The restoration of function by a second mutation in the same gene is known as a suppressor mutation.
Step-by-step explanation:
The restoration of function by a second mutation at a different site in the same gene is known as a suppressor mutation. This type of mutation can counteract the effects of the initial mutation, leading to a restoration or modification of the gene's original function. It is important to note that an inducer typically refers to a molecule that initiates gene expression, while a reversion is a mutation that reverses the effects of a previous mutation, restoring the original phenotype. An enhancer is a DNA sequence that promotes transcription and is not responsible for restoring gene function after a mutation.