Twice a day the tide moves from london to the ocean and

Can someone me? i need to have this done as soon as possible! i'm putting 20 points on this!

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.

Which of the following is not a reason why shenzhen, china, is considered an emerging global city