I need help please. I don't understand

C, identify the problem

Explanation:

The Engineering Design process goes like this:

1) Identify the problem

2) Collect information

3) Brainstorm & analyze ideas

4) Develop solutions and build a model(prototype)

5) Present your ideas to others for feedback/ test your model

6) Improve your design  

Hoped that helped ;)

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.

b. examine and describe cells