Introduction:
In the process of reproduction, the fusion of male and female gametes leads to the formation of a zygote, which is the beginning of the life of the organisms.

Zygote:
A zygote is a fertilized egg cell formed by the fusion of a sperm and an egg. It contains all the genetic information required for the development of a new individual. The zygote undergoes cell division and differentiation to form an embryo.

Cell:
A cell is the basic unit of life. It is the smallest living entity that can carry out all the functions of life, such as metabolism, growth, and reproduction. Cells are the building blocks of tissues and organs.

Tissue:
A tissue is a group of cells with a similar structure and function. Tissues work together to form organs, which carry out specific functions in the body. There are four main types of tissues in the body: epithelial, connective, muscle, and nervous.

Embryonic Layer:
The embryonic layer is the innermost layer of cells in the early embryo. It gives rise to all the tissues and organs of the developing embryo. The embryonic layer undergoes complex processes of cell division, differentiation, and migration to form the various structures of the developing organism.

Conclusion:
In conclusion, the zygote is responsible for the beginning of the life of the organisms. It gives rise to all the cells, tissues, and organs of the developing embryo through complex processes of cell division, differentiation, and migration.

Cells are responsible for beginning of the life of the organisms.