There should be no 'and' in there. The sentence should go like this:
The man is a scientist with a keen sense of observation who dedicates long hours in the lab.
Observations
The job of a scientist is to study natural phenomena with the aim of understanding and perhaps utilizing these occurrences. The study of earthquakes is seismology, and a scientist who studies them is a seismologist.
The basis for historical knowledge is not empirical facts but written text, observation alone is not sufficient
to learn
Sentence A describes liquids best, although sentence B also fits the description of liquids.
I can give you several sentences.Careful observation will reveal that the burglar had a key.The scientist began his observation of the strange rock.You powers of observation are amazing.
Thank you for your astute observation.
Observation
The verb in that sentence is describes.
Scientist
Scientists often find that quantitative observation is more important than qualitative observation.
the scientist chewed bubble gum :)
Systematic Observation was one suggestion given to the employer by the manager. This is an example using the word systematic observation.
The best description of a scientific theory is the last one that you offered, that it is well tested and it explains a wide range of observation.
Example sentence - He studied many hours to become a scientist and was well rewarded for his efforts.
It is an observation because you can see that the cat is ill so it is visual.
a descriptive sentence is a sentence that describes something in one sentence