Correct Answer: (4) increasing human population
More food must be produced in order to sustain the increasing human populatison. Because of this, more natural habitats were disrupted and used for agriculture. Agriculture also disrupts the nitrogen cycle. This also causes great loss of biodiversity.
When fossil fuels are burned (for human activities like in factories, vehicles, etc.), the concentration of carbon dioxide in the atmosphere increases. This further causes global warming that induces dramatic climate changes in the whole planet.
Humans also dump toxic materials in the environment which causes biological magnification of toxic products accumulation in organisms at the topmost level of the food chain.
These are just some of the several activities of humans that greatly affect the ecosystems of the Earth.
Use of air pollution controls and use of natural predators to control insect pests have no negative effects on the ecosystem, consequently, they prevent the disruption of ecosystems.
Recycling of glass, plastic and metals were also done to prevent ecosystem disruption. However, there were some studies that they can also be harmful to the environment, especially when they are combusted during the process.