A list of words is given in a box. Use appropriate words to fill up the blanks in the following statements
Air, oxygen, wind, water vapour, mixture, combination, direction, road, bottles, cylinders.
(a) The ______ makes the windmill rotate
(b) Air is a ______ of some gases.
(c ) A weather cock shows the ______ in which the air is moving at that place.
(d)Mountaineers carry oxygen ______ with them, while climbing high mountains.

Explanation

To solve the problem, we need to fill in the blanks with the appropriate words from the provided list. Let's go through each statement step by step.

### Step-by-Step Solution:

(a) The ______ makes the windmill rotate.
- **Analysis**: A windmill rotates due to the force of moving air.
- **Answer**: The **wind** makes the windmill rotate.

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