White muscle fibres, also known as fast-twitch fibres, are one of the two types of muscle fibres found in skeletal muscles. These fibres are characterised by their ability to contract quickly and powerfully, but they tire easily. Here's an explanation of the given options and why option 'D' is the correct answer:

A) Presence of plenty of mitochondria

- Mitochondria are the organelles in cells that produce energy in the form of ATP through cellular respiration.
- White muscle fibres have fewer mitochondria compared to red muscle fibres, which are characterised by their endurance and aerobic capacity.
- Therefore, the presence of plenty of mitochondria is not a characteristic of white muscle fibres.

B) High myoglobin content

- Myoglobin is a protein that stores oxygen in muscle cells.
- Red muscle fibres have a higher myoglobin content than white muscle fibres, as they rely on aerobic respiration for energy production.
- White muscle fibres have a lower myoglobin content because they use anaerobic respiration, which does not require oxygen.
- Therefore, high myoglobin content is not a characteristic of white muscle fibres.

C) Low amount of sarcoplasmic reticulum

- The sarcoplasmic reticulum is a specialized type of endoplasmic reticulum that stores and releases calcium ions to trigger muscle contraction.
- Both white and red muscle fibres have sarcoplasmic reticulum, but the amount may differ depending on the muscle's function.
- Therefore, a low amount of sarcoplasmic reticulum is not a characteristic of white muscle fibres.

D) They depend upon anaerobic process of respiration for energy

- White muscle fibres rely on anaerobic respiration for energy production, which does not require oxygen.
- This process involves the breakdown of glucose into pyruvate, which is then converted into lactate.
- Anaerobic respiration is less efficient than aerobic respiration and produces less ATP, but it can provide energy quickly for short bursts of intense activity.
- Therefore, white muscle fibres depend on anaerobic respiration for energy, which is a characteristic of these muscle fibres.

In conclusion, the correct answer is option 'D' because white muscle fibres depend on anaerobic respiration for energy production.

White muscle fibres have high amount of sarcoplasmic reticulum and less amount of myoglobin and mitochondria. So, they depend upon anaerobic process of respiration for energy.