The answer to your question would be a joint
The answer is fertilization.
Fertilization is when the sex cells' nuclei (the nucleus of both an egg and a sperm) combine. After fertilization, the male and female chromosomes will have also joined together to create a new combination of DNA for the offspring.
That phrase if you don't use it you will lose it stands true.
I believe that the answer would be C. It is the only one that makes the most sense with the question.
Hope this helps!
