By what process will fertilized egg grow?

A fertilized egg, also called a zygote, grows through a process called embryonic development. This is a complex and fascinating series of events that can be broadly divided into three main stages:

1. Cleavage:

- The zygote undergoes rapid cell division, called cleavage, without significant growth in size. This creates a ball of cells called a morula.

- Cells continue to divide, forming a hollow ball called a blastocyst.

2. Gastrulation:

- Cells within the blastocyst rearrange themselves into three germ layers:

- Ectoderm: Forms skin, nervous system, and some sense organs.

- Mesoderm: Forms muscle, bone, blood, and circulatory system.

- Endoderm: Forms lining of digestive and respiratory systems.

- This process establishes the basic body plan.

3. Organogenesis:

- The germ layers differentiate further, forming specific organs and organ systems.

- This stage involves complex interactions between cells, growth factors, and genetic programs.

Key Processes Involved in Embryonic Development:

- Cell division: Rapid cell multiplication creates the necessary number of cells for the developing embryo.

- Cell differentiation: Cells become specialized to form different tissues and organs.

- Morphogenesis: The development of the shape and form of the embryo.

- Growth: The overall increase in size of the embryo.

Regulation of Development:

- Genes: Specific genes are activated or deactivated at different stages of development, controlling cell division, differentiation, and morphogenesis.

- Growth factors: These proteins act as signals to influence cell growth and differentiation.

- Environment: External factors like nutrition and temperature also play a role in development.

Note: This is a simplified overview. Embryonic development is a complex and highly regulated process that varies between species. There are many other important factors and processes involved that are not mentioned here.