Q. A matured mammalian cell without nucleus is

Explanation by: Praveen Singh

A matured mammalian erythrocyte (red blood cell) is unique in that it does not have a nucleus. During its maturation process, the nucleus is expelled to make more room for hemoglobin, which is essential for oxygen transport. This adaptation allows the red blood cell to carry more oxygen efficiently.

The other options:

    Lymphocyte is a type of white blood cell with a nucleus.
    Spermatozoan has a nucleus in its head, which contains genetic material.
    Oocyte (egg cell) also has a nucleus.