Introduction:
Proteins are essential macromolecules found in the main solid parts of all living cells. They play a crucial role in various biological processes and are necessary for the proper functioning of the human body. However, there are a few errors in the given statement that need to be addressed.

Errors in the statement:
1. "They are find in milk, meat and fish." - The correct word should be "found" instead of "find."
2. "They are a must to the body to unable it to build in new cells or repair old ones." - The correct phrase should be "They are essential for the body to enable it to build new cells or repair old ones."
3. "for this reason grow children need more proteins than adults." - The correct phrase should be "for this reason, growing children need more proteins than adults."
4. "Since children were more active than adults and use most?" - The correct sentence should be "Since children are more active than adults and use up more energy."

Importance of Proteins:
- Building and Repairing Cells: Proteins are the building blocks of cells. They are involved in the synthesis of new cells and the repair of damaged ones. This is crucial for growth, development, and maintaining the overall health of the body.

Protein Sources:
- Milk: Milk is a rich source of protein, particularly casein and whey proteins. These proteins provide essential amino acids necessary for the body's growth and repair processes.
- Meat: Meat, such as chicken, beef, and pork, is a complete source of protein. It contains all the essential amino acids required by the body.
- Fish: Fish is another excellent source of protein. It is also rich in omega-3 fatty acids, which are beneficial for brain health.

Protein Requirements for Children:
- Growth and Development: Children undergo rapid growth and development, requiring more protein to support the building of new tissues, organs, and muscles.
- Increased Activity: Children are generally more active than adults, engaging in various physical activities. Protein is essential for providing energy and repairing muscle tissues damaged during exercise.

Conclusion:
Proteins are vital for the human body as they are involved in building new cells and repairing old ones. They can be found in milk, meat, and fish, which are excellent sources of protein. Growing children require more proteins compared to adults due to their increased energy expenditure and rapid growth. Ensuring an adequate protein intake is essential for maintaining optimal health and supporting the body's various physiological processes.

Its protein not proteins after more...