Formation of antibodies within our body is called Active Immunity.

Explanation:

Active immunity is a type of adaptive immunity that occurs when our immune system is exposed to a pathogen or foreign substance, and then produces an immune response that includes the production of antibodies. Antibodies are proteins produced by the body's immune system in response to the presence of a foreign substance, such as a virus or bacteria. They help to identify and neutralize the foreign substance, thereby protecting the body from infection.

There are two types of active immunity:

1. Natural active immunity: This occurs when our body is exposed to a pathogen in the natural environment, such as through an infection, and then produces an immune response that includes the production of antibodies. This type of immunity can last for many years, and in some cases, for a lifetime.

2. Artificial active immunity: This occurs when our immune system is exposed to a pathogen or foreign substance in a controlled manner, such as through a vaccine. The vaccine contains a weakened or dead version of the pathogen, which stimulates the immune system to produce an immune response that includes the production of antibodies. This type of immunity can also last for many years, and in some cases, for a lifetime.

In summary, the formation of antibodies within our body is a key component of active immunity, which is a type of adaptive immunity that provides long-term protection against pathogens and foreign substances.

Answer is acquired immunity
acquired immune response is of two types - antibody mediated and cell mediated.
when any pathogen 1st time enters in our body, B-lymphocytes produce proteins in response to pathogens into our blood to fight with them .These proteins are called antibody
(ncert page -151)