What happens at each step of a dichotomous key?

me!

Oh I know this, It narrows down its characteristics here is an example:

The first step in the key will be organized the following way:

1. a. wings covered by an exoskeleton

b. wings not covered by an exoskeleton

Next, the statements need to lead the observer to the next step to narrow the identification further:

1. a. wings covered by an exoskeleton go to step 2

b. wings not covered by an exoskeleton .go to step 3

Step 2 needs to consist of a pair of statements that will allow for the identification of the ladybug and the grasshopper:

2. a. body has a round shape .ladybug

b. body has an elongated shape .grasshopper 

the correct option is option d