Quaternary consumers eat the tertiary consumers and are carnivores. These consumers are typically carnivorous animals. In my opinion, all ecosystems necessarily should have a quaternary consumers. This is because they complete the food chain. In every, ecosystem you can see these consumers.
Water is a limited resource, despite it being very useful. We still use it very often because there is a bountiful amount of it, but it is not abundant, obviously we have enough to last you and I, but we will eventually run out. If anything, it'll become rarer and increase in price, but I have a feeling we will either find water somewhere else, or die out before then.
Biomagnification, also known as bio amplification or biological magnification, is any concentration of a toxin.
The correct formulae is CCl4