In the immune system, the thymus is considered as a primary lymphoid organ. Thymus is present behind the sternum, above the heart and between the two of our lungs. It is made up of two-lobed and is involved in releasing hormones and providing immunity.
Thymus is the primary site where T- cells become mature. T- cells are formed in bone marrow but reaches to thymus for maturation. These mature T- cells play a very important role in providing adaptive immunity against foreign molecules.
Thymus is larger till puberty and it slowly shrinks as the age increases. So the correct answer is thymus.
if sex cells were identical, there won't be genetics variations and we will just all be identical to our parents. genetic variation allows us to better adapt and survive