Answer:
A mistake in the DNA of a body cell, such as a brain cell, would only affect that particular cell and its daughter cells produced through mitosis. This is because DNA mutations occurring in body cells are not passed on to offspring during reproduction.
In contrast, a mistake in the DNA of a germ cell, such as a precursor cell that eventually develops into a sperm cell, can be passed on to the offspring during reproduction. This is because germ cells undergo meiosis to form gametes (sperm or egg cells), and any mutations in their DNA can be passed on to the next generation.
Therefore, mistakes in the DNA of germ cells have implications for the genetic makeup of future generations, while mistakes in the DNA of body cells only affect the individual organism in which they occur.