NEET BIOLOGY

Detailed explanation-1: -Cancers is the result of loss of multicellular traits; thus, it is a disease of multicellularity. Caveat: Many of the so-called multicellular traits are also expressed by unicellular organisms and their loss can result in cancer-like mutants.

Detailed explanation-2: -This is consistent with the observation that neoplasms are not exclusive to high-order organisms but appear across the entire range of multicellular organisms, including metazoans, fungi, plants and algae (Aktipis et al, 2015).

Detailed explanation-3: -Cancer is widespread in the animal kingdom; it affects molluscs, fish, reptiles, birds and mammals. Some species develop cancers very similar to humans, while others are affected by a rare, contagious form of the disease. At the other end of the spectrum, some species rarely get cancer.

Detailed explanation-4: -The simple answer is no-single-celled organisms cannot become cancerous. Since a complete organism consists only of one cell, it does not have multicellular tissues from which a tumor could arise.

Detailed explanation-5: -Cancer represents a breakdown of molecular mechanisms evolved by multicellular life to impose constraints on cell growth, resulting in more “primitive” proliferative cellular phenotypes.