Answer: It would probably be A.
Explanation: Abrasion means scraping or wearing away. Therefore the correct sample is probably going to look smaller, smoother, and more even from all the scraping of the river currents.
Hope that helps!
Answer:
A set of practices that humans can follow to meet their needs without causing long-term, negative effects on species or ecosystems.
Explanation:
Sustainability means "the ability to be maintained at a certain rate or level." So sustainability is the ability for humans to meet their needs, while also maintaining the ecosystem and different species at the same rate and level.