1. Why do you think that sexual reproduction is considered a pillar of evolutionary advancement? Practically all species (except the most simple) have the ability to reproduce sexually. What do you think are the evolutionary advantages of sexual as opposed to asexual reproduction?
2. One of the most common chromosomal abnormalities is Trisomy 21, or Down’s Syndrome resulting from three copies of chromosome 21. This occurs in about one baby in 600. Characteristics of Down syndrome include rounded features, an enlarged tongue that often protrudes, and various internal disorders. Trisomy 21 occurs more frequently among babies born to women over 35 years old. The age of the father has little or no effect. What do you think are possible reasons leading to this meiotic nondisjunction in female eggs?
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