The phenomenon of nuclear fusion of sperm and egg is known as:
Karyogamy
The correct answer is option C.
Explanation of the correct option:
Explanation of the incorrect options:
Option A:
Parthenogenesis is a type of reproduction in which an egg develops into an embryo without the need for sperm to fertilize it.
Option B:
It is a type of gametogenesis in which ova (female gametes), are created and the resulting female gamete is called an ovum.
Option C:
The process of vitellogenesis is the formation and accumulation of the yolk in the ovum.
Final answer: The phenomenon of nuclear fusion of sperm and egg is known as karyogamy.