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