Final answer:
The variation in offspring of Otis and Anne is due to sexual reproduction, which involves a combination of genetic traits from both parents. During meiosis, genetic material is shuffled and recombined, contributing to genetic diversity. Mutations can also occur, leading to new traits in the offspring.
Step-by-step explanation:
The variation in offspring of Otis and Anne, the spiders, is due to the process of sexual reproduction. In sexual reproduction, offspring inherit a combination of genetic traits from both parents. This results in genetic variation, making the offspring not identical to their parents.
During the formation of reproductive cells (gametes), such as sperm and eggs, a process called meiosis occurs. Meiosis involves the shuffling and recombination of genetic material, which further adds to genetic diversity. When the sperm and egg unite during fertilization, the offspring receive a unique combination of genes from their parents.
Additionally, mutations can occur during DNA replication or as a result of external factors, further contributing to variation in offspring. Mutations are random changes in the DNA sequence and can lead to new traits or characteristics in the offspring that were not present in the parents.