Question

Myelin sheath is a layer covering

• A. A nerve fibre in a vertebrate
  
• B. A chick embryo
• C. A muscle fibre in a vertebrate
• D. None of the above

Answer 1

The correct option is A A nerve fibre in a vertebrate

The axon can be defined as the long cytoplasmic process of the cell body, which transmits the impulse from the cell body to other neurons. The axon of the neuron is covered by a lipid-rich membrane, called myelin sheath. The myelin sheath is formed by Schwann cells and each Schwann cell covers a part of the axon.
Thus, the correct answer is the option D.