请教两道语法题

fastalingerUID: 181399

(Because )it is often dependent of the conditions of crystallization,the cimposution of the (minerals)in a rock's can be important (in determining) the rock's geo;ogic history.
commercial expension from city to subsurb has affected the way people in the Unted States (live and work ) 这是正确选项 为什么？：）
Snakes are capable of graceful (motion) throughout the entire (long) of their rubbery bodies.我觉得long 错拉应改为length  可答案选motion