When they join people use the term FUSES
SORRY BEST I COULD DO
The cell that fertilises the egg cell is called the sperm cell. _-------O That's how a sperm cell looks like <<<<<<<<<<<<<<<<<
A sperm and an egg.
the egg is larger than the sperm cell
Twenty-three chromosomes are in a cell that is formed from a sperm and egg cell.
In animals it would be called a sperm. In plants I assume the answer would be the pollen, however, the pollen is not necessarily one cell. Even if it is one cell it will have more than one nucleus (2 or 3).
A sperm cell is called a spermatozoon.
The cell that fertilises the egg cell is called the sperm cell. _-------O That's how a sperm cell looks like <<<<<<<<<<<<<<<<<
It's a fertilized egg. It can also be called a zygote.
Gamete (a male or female sex cell ie the egg or the sperm)
Zygote .
A sperm and an egg.
the egg is larger than the sperm cell
The uniting is known as fertilisation of the egg by the sperm.
egg by far
Twenty-three chromosomes are in a cell that is formed from a sperm and egg cell.
FERTILIZATION
Egg cells are the biggest: you could only fit one on the head of a pin. But I'm not sure if a sperm cell is bigger than a red blood cell or vice versa.