Exploitation of natural resources means using things from nature to make our lives easier. This can include things like cutting down trees to make wood for building, or taking rocks from mountains to build roads. It also includes things like taking water from rivers for drinking and making power, or taking oil and natural gas from the ground for energy. Taking these things from nature does not harm it, but it does mean that we need to be careful with how much we take, otherwise we would run out of them.