Answer: The human body is organized at different levels, starting with the cell. Cells are organized into tissues, and tissues form organs. Organs are organized into organ systems such as the skeletal and muscular systems
Explanation:
Answer:
True.
Explanation:
Antigen may be defined as the chemical that has the ability to evoke the and immune response and can harm the living organisms. The specific antibody are produced against the immune response.
The antigens has evolved different mechanisms to prevent themselves from them the immune system of the host. The antigenic shift is the most common change that might occur in viruses that helps the antigen to protect itself by changing its genetic material. No anti viral drugs are available for the viruses.
Thus, the answer is true.
Answer:
25 years
Explanation:
Ossification is the process of bone tissue formation. Osteoblasts are responsible for the process of ossification. It begins when the fetus is three months old and goes on till 25 years of age. Upper limbs get ossified first, followed by lower limbs, sternum and vertebrae.
There are two types of ossification processes. When bone is directly developed using the primitive connective tissue (mesenchyme) it is called as intramembranous ossification, while in endochondral ossification cartilage is used as a precursor.