Answer:
3,4
Explanation:
Hydrogen has no other electron hence there is no screening of the valence electron by inner electrons. It is the lightest known element with a relative molecular mass of 2. Screening effect refers to the fact that inner or core electrons prevent the outermost electron from feeling the attractive force of the nucleus.
The planets speed as they orbit the sun
Answer: Cornea
Explanation: The cornea is the only part of a human body that has no blood supply as it gets oxygen directly through the air.
That's cool man, you should study more... wheres the question though?
