Answer:
The right option is d. observation
Explanation:
Observation: These is the state of being very alert about the what is happening around. Observation in science can be done using the sense organs such eyes to spot out differences, nose to smell the release of gases, ears to hear sound, skin to feel changes in temperature. Observation is the first scientific method. And it can be carried out anywhere.
Observation leads pattern, pattern leads to problems, problems leads to hypothesis, hypothesis leads to experiment, experiment leads to Theory.
Therefore the right option is d. observation
