Read the given Statements .
(i) A motor neuron along with the muscle fibres connected to it constitutes a neuromuscular junction.
(ii) During muscles relaxation , `Ca^(++)` are pumped back from sarcoplasm to the cisternae.
(iii) Aerobic muscles have a large number of Mitochondria to utilize a large amount of oxygen for generation of ATP.
(iv) Red muscles have high myoglobin content.
Which of these is/are INCORRECT ?

Options

A. i only
B. i,ii, iv
C. iii, iv
D. None of these

Answer

To determine which statements are incorrect, let's analyze each statement one by one:

1. **Statement (i)**: "A motor neuron along with the muscle fibres connected to it constitutes a neuromuscular junction."
- **Analysis**: This statement is incorrect. A neuromuscular junction is actually the synapse or connection between a motor neuron and a muscle fiber, but it does not include the muscle fibers themselves. The motor neuron communicates with the muscle fiber at this junction, but they are not collectively referred to as a neuromuscular junction.

2. **Statement (ii)**: "During muscle relaxation, Ca²⁺ ions are pumped back from the sarcoplasm to the cisternae."
- **Analysis**: This statement is correct. During muscle relaxation, calcium ions (Ca²⁺) are indeed pumped back into the sarcoplasmic reticulum (cisternae), which helps the muscle fibers to relax.

3. **Statement (iii)**: "Aerobic muscles have a large number of mitochondria to utilize a large amount of oxygen for generation of ATP."
- **Analysis**: This statement is correct. Aerobic muscles, which rely on oxygen for energy production, do have a high density of mitochondria to facilitate ATP generation through aerobic respiration.

4. **Statement (iv)**: "Red muscles have high myoglobin content."
- **Analysis**: This statement is also correct. Red muscles (often associated with slow-twitch fibers) contain a high amount of myoglobin, which helps in oxygen storage and transport within the muscle.

**Conclusion**: The only incorrect statement is (i).

### Final Answer:
The incorrect statement is (i) only.

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