The fusion of these two cells is called fertilization and it produces a diploid cell with 46 chromosomes - twice the amount found in each gamete. The fertilized egg is now called a zygote and has just the right amount of DNA needed for normal human development.

Explanation:

After fertilization, the cell that is formed is called a zygote. The zygote is the first cell of a new individual and marks the beginning of the development process.

Formation of Zygote:
- Fertilization is the process in which a sperm cell and an egg cell fuse together to form a zygote.
- During sexual reproduction, the sperm cell from the male and the egg cell from the female join together during sexual intercourse.
- The sperm cell carries genetic material in the form of chromosomes, and so does the egg cell. When they combine, the genetic material from both parents is brought together in the zygote.
- The fusion of the sperm and egg results in the formation of a zygote with a complete set of chromosomes, half from the mother and half from the father.
- This process usually occurs in the fallopian tube of the female reproductive system.

Characteristics of Zygote:
- The zygote is a single cell that contains all the genetic information necessary to develop into a new individual.
- It undergoes cell division and differentiation to form an embryo.
- The zygote is diploid, meaning it has two sets of chromosomes (one from each parent) and is capable of developing into a complete organism.

Importance of Zygote:
- The zygote is the starting point of embryonic development, where all the necessary genetic information for the new individual is present.
- It is the first step in the formation of a new organism, whether it is a plant, animal, or human.
- The zygote divides and undergoes further development to form a multicellular organism.
- The zygote carries the genetic traits and characteristics of both parents, which are passed on to subsequent generations.

In conclusion, the correct answer is option 'B', which is zygote. The zygote is the cell formed after fertilization and marks the beginning of the development process.

Fertilisation is the fusion of male and female gamets

Male and female gamets combine to form a zygote