Final answer:
Extra copies of somatic chromosomes are generally fatal due to the severe developmental disorders they cause. Exceptions like certain trisomies can lead to survival, but with significant challenges. Chromosome abnormalities disrupt vital genetic balance needed for development.
Step-by-step explanation:
The question pertains to whether extra copies of somatic chromosomes are fatal. True is the correct answer, as having additional chromosomes, known as aneuploidy, usually results in a non-viable embryo or severe developmental disorders. Every somatic cell typically has two copies of each chromosome, apart from gametes which only carry one. However, when nondisjunction occurs during meiosis, gametes may end up with an abnormal number of chromosomes, leading to conditions like monosomy or trisomy. Most autosomal trisomies result in non-viable embryos, with the exception of certain trisomies such as those involving chromosomes 13, 15, 18, 21, or 22, which can lead to survival, but with significant functional challenges and developmental delays, such as in the case of Down Syndrome.
The lethal nature of extra chromosomes or missing chromosomes demonstrates the critical balance required for proper development and function. Chromosome abnormalities can have profound effects on health, and while some individuals with specific trisomies can survive, the complications associated with these conditions often lead to a reduced lifespan and quality of life.