A concrete noun is used through your five senses. They can be:
-Common nouns
-Proper nouns
-countable and uncountable nouns
-collective nouns
I hope this helps.
<span>The correct answer is A. the results of a scientific study would be the most effective evidence. Thoughts and opinions are not valid for scientific studies because they are based on emotions and personal values. Ethics also have a problematic effect on science because values and morals are often different from society to society.</span>
Where is the story at how can I help you
Taught is in past tense, when you say he taught it means he has already done it