Answer:
A. observing
Step-by-step explanation:
There are various steps that are involved in a scientific investigation. Observation is the first step of the scientific investigation. In this step, a close examination is laid on the investigation. Observation is collected with the senses and the information is gathered.
In the given excerpt, Clive missed the observation part of the scientific investigation. All the other three steps were followed by Clive. He was not able to observe the situation and so was not able to provide the answers to the questions asked by his classmates.