What is a convection current?

Why is terracing used in southeast asian agriculture?

Which of the following is the main purpose of using an anchored network of booms which funnel debris to a collection area?

You have been tasked with sorting the rock samples shown into three categories, with two rocks in each category. what attribute would you use to sort these rocks? which rocks would be in each category? rocks: obsidian, coquina limestone, granite, soapstone,pumice, and gneiss.