Explanation:

- Tree plantation is the (1)______ of transplanting saplings or seeds to maximise the amount of greenery and focus on promoting

- Options could include "process," "act," or similar terms that refer to an action or activity.

- (2)______. Planting trees can be a very rewarding and fruitful

- This blank would likely be filled with something related to an outcome or purpose like "biodiversity" or "greenery."

- (3)______! Not only is it (4)______ beneficial for this planet, but it also contributes to helping create an environmentally friendly place to live, as trees help reduce pollutant

- Options for (3) could be "activity," "endeavor," or similar terms implying engagement.

- For (4), suitable words may include "immensely" or "greatly" which provide emphasis.

- (5)______

- Options:

1. Problem: This doesn't fit well as it refers to an issue rather than a quantity.

2. Concentration: This fits well as it refers to the quantity of pollutants, which trees help to reduce.

3. Method: Not suitable, as it refers to a way of doing something rather than a quantity.

4. Calculation: Incorrect, as it refers to the act of calculating rather than a quantity.