'Gemmule formation is a common mode of reproduction in Paramecium'

Which of the following is correctly matched?

In $Ophioglossum$ (a fern),the chromosome number in a gamete is ..... and in potato,the chromosome number in a gamete is ....

Select the correct option for the zygote.
$I -$ It is found only in organisms undergoing sexual reproduction.
$II -$ It is always diploid $(2n)$.
$III -$ It is also known as a fertilized egg.
$IV -$ It is always formed as a result of fertilization or syngamy.
$V -$ It is the link between two generations.

Which of the following organisms possess the power of regeneration?

In diploid organisms,the gamete-producing cells are called: