1
A material like very thick, stiff paper, usually pale brown in colour, used especially for making boxes.
2
To cause to fill or become covered with water, especially in a way that causes problems.
3
Unwanted matter or material of any type, especially what is left after useful substances or parts have been removed.
4
The process of collecting and changing old paper, glass, plastic, etc. so that it can be used again.
5
A gradual increase in world temperatures caused by gases such as carbon dioxide that are collecting in the air around the Earth and stopping heat escaping into space.
6
Animals and plants that grow independently of people, usually in natural conditions.
7
A hard substance that forms the branches and trunks of trees and can be used as a building material, for making things, or as a fuel.
8
An elastic substance made either from the juice of particular tropical trees or artificially.
9
An artificial substance that can be shaped when soft into many different forms and has many different uses.
10
A forest in a tropical area that receives a lot of rain.
11
The soft, thick hair that sheep and some other animals have.
12
The number and types of plants and animals that exist in a particular area or in the world generally, or the problem of protecting this.
13
The cutting down of trees in a large area, or the destruction of forests by people.
14
A long period when there is little or no rain.
15
A type of animal or plant that might stop existing because there are only a few of that type alive.