the jelly like fluid is called cytoplasm
It looks like you got everything correct except for the big thing in the middle which is the vacoule. It should be colored light blue. The far bottom left where you have it colored light blue is the Golgi apparatus and that should be colored dark blue. Everything else looks pretty good.
DNA acts as a sort of set of instructions for building an organism.
In that way, different types of organisms--plants, animals, bacteria, etc.--can all be differentiated through their DNA because it is directly linked to how they function.
A dichotomous key helps you identify unknown specimens based on their traits because there are only two options available per trait. Selecting one from the two options (usually contrasting characteristics) from each step leads to smaller and smaller groups until the option is reduced to single and unique trait of an organism.
Considering you need to identify an organism. So, on the top of they key is animal with options: (a) with red blood cells and (b) no red blood cells. The option you will select is no red blood cells and under option b, you’re given two choices again: (a) hard bodies and (b) soft bodies. You’ll select soft bodies, then two options again are given: (a) with shell and (b) without shell. The option you’ll select would be without shell, and so on.