1) Sustainability, as the word implies, is about having something to be sustained, hence preserved in time. It is thus a, the method of ensuring that resources are available in the future too. While b is important for the environment and can also lead to a push for sustainable development, the correct definition is a. C is wrong and it is often the case that it does not help sustainability.
2) Again, we can knock out logging as a choice since this is using natural resources. A and B seems like a tempting answer but be careful! The sun's energy is infinite, so it does not need to be conserved. You do not conserve something by using it, even if you are helping the environment. Plastic and metals are a finite resource though and recycling helps conseve them. Thus, recycling is the correct answer.
3) All 3 actions might help endangered species but the Endangered Species Αct is centered around protecting threatened and endangered animal populations by law. This might be achieved with the preservation of resources (stopping logging etc.) but the scope of this Act is more broad.
