The surest way to combine the best qualities of both parents in the offspring is...

Explanation

In Biology, offspring inherit traits from their parents. Sometimes, these traits are desirable, and people want to combine them to get the best qualities in their offspring. The question is asking about the surest way to do this. The options provided are cross-breeding, inbreeding, selective breeding, and all of the above. The correct answer is cross-breeding. Cross-breeding involves breeding two different individuals with desirable traits to produce offspring that inherit the best qualities of both parents. This method helps to increase genetic diversity, which is important for the survival of the species. Inbreeding, on the other hand, involves breeding closely related individuals, which can increase the probability of genetic diseases and decrease genetic diversity. Selective breeding involves choosing individuals with desirable traits and breeding them to produce offspring with those traits. This method can be effective but can also reduce genetic diversity if not done carefully. Therefore, the best way to combine the best qualities of both parents in the offspring is through cross-breeding. To learn more about this, please read the relevant sections of the recommended textbooks.