Answer: The answer is B.Sonar and C.Radar
Explanation:
They are both just like an echo which is the main things that uses reflected sound waves. They are basically like synonyms for echo.
Answer:
Element X has valency 2 while Y Valency 2, element Y has high tendency of gaining electrons for its stability thus the compound formed will be B
elements X is positively charged while Y will be negatively charged
Answer:
A. Semi Permeable.
Explanation:
Cell membranes are semi permeable.