Final answer:
The statement is false because a zygote with 45 or 47 chromosomes is the result of nondisjunction, not random fertilization. Nondisjunction can lead to aneuploidy, resulting in monosomy or trisomy.
Step-by-step explanation:
The statement 'If a human zygote has either 45 or 47 chromosomes, it was caused by random fertilization.' is false. Typically, a human zygote has 46 chromosomes - 23 from an egg and 23 from a sperm. However, if it has 45 or 47 chromosomes, this is not due to random fertilization, but rather the result of a chromosomal abnormality called nondisjunction. Nondisjunction occurs when the chromosomes fail to separate properly during the meiosis process of the sperm or egg, leading to gametes with an abnormal number of chromosomes - either one extra or one missing (aneuploidy). Upon fertilization, these gametes result in zygotes with 45 (monosomy) or 47 (trisomy) chromosomes, which may lead to certain developmental disorders or genetic conditions in the fetus.