NEET Biology 4

Question 1

Which type of immunity involves memory cells that respond faster upon second exposure to an antigen?

Accepted Answer

Active acquired immunity

Answer

Active acquired immunity involves B and T memory cells that enable a rapid, enhanced secondary immune response upon re-exposure.

Question 2

In a dihybrid cross between AaBb × AaBb, what fraction of offspring will show both dominant traits?

Accepted Answer

9/16

Answer

Using the product rule, 3/4 (dominant for A) × 3/4 (dominant for B) = 9/16 show both dominant phenotypes.

Question 3

Pneumatophores are aerial roots seen in:

Accepted Answer

Rhizophora (mangroves)

Answer

Pneumatophores are negatively geotropic roots in mangroves like Rhizophora that project above waterlogged soil for gas exchange.

Question 4

The fluid mosaic model of cell membrane was proposed by:

Accepted Answer

Singer and Nicolson

Answer

Singer and Nicolson proposed the fluid mosaic model in 1972, describing the membrane as a fluid phospholipid bilayer with embedded proteins.

Question 5

Which of the following is an example of mutualism?

Accepted Answer

Mycorrhizae with plant roots

Answer

Mycorrhizae (fungi + plant roots) is mutualism: fungi improve nutrient uptake for the plant and receive photosynthates in return.

NEET - National Eligibility cum Entrance Test Practice Test