Answer:
Germline cells
Step-by-step explanation:
Germline cells, also known as se.x cells or zygotes, are the cells that are responsible for passing along the genetics of an individual to the offspring.
There is only one copy of each chromosome in these cells because they fertilize (combine) with another individual's germline cell to create the offspring. If there were more than one copy, the resulting offspring would not have diploid chromosomes.