What technological challenges are present in bringing back extinct species?

The main challenge will be

1. Difficult to find the cells of extinct species.

2. If we revived an extinct species, then to give their natural habitat will be difficult in this current situation.

Explanation:

There are a lot of species are daily wiping out from the earth daily. So, it is important to bring them back from extinction. Cloning is the most preferred method used to bring back the extinct species. In cloning, they will extract the nucleus from the preserved cell and swap with the nearest living relative of the extinct species. Then this egg will insert into the relative host. But finding the cell of the extinct species are really difficult. Our anthropologists are working very hard to make it.