I believe the answer is this:
DNA replication is called semi-conservative because half of the original double-helix appears in one daughter strand formed in replication if you need any more help then please comment and let me know ok. :)
The most likely explanation for the variation is the offspring were produced from different combination of genes. A single pair of gold fish mentioned in the question means a male and a female gold fish. The two of them mated and contributed different genes to the fertilized fish eggs, this results in production of various body shape and colouration which is known as variation.
The correct answer is a muscle tissue, more precisely cardiac muscle tissue. <span>Cardiac muscle tissue consists of individual cardiomyocytes (heart muscle cells) which are connected by intercalated discs to work as a single functional organ. The function of intercalated discs is to support synchronized contraction of cardiac muscle.</span>
Do You have a picture of what you’re trying to figure out