URGENT: AQA GCSE Biology (B1) - Confused about auxin

It basically means auxin helps to make plants grow, as auxin is a hormone. It is produced in the tips of the plant and it moves within the plant to stimulate growth behind the tips of the plant. For example; when the plant is being exposed to light, auxin will start to produce in the shaded part of the plant which then stimulates growth within that area, making the plant grow more on shaded side than the exposed side making the plant bend so it is exposed to more light for photosynthesis (to survive). Auxin helps plants to survive basically. Hope this helps

Also the difference is when auxin accumulates in shoot it stimulates growth but in the root it inhibits growth.

To anyone who knows about biology, what does this mean?

"Auxin is produced in the tips and moves backwards to stimulate the cell elongation which occurs in the cells just behind the tips."

Also, what are roots and shoots? What is the difference?

(I'm revising plant hormones from AQA GCSE Biology - Unit 1).