Every object with mass exerts a gravitational force on every other object with mass in the universe. does something, who knows.

stays the same

decreases

increases

because growing process had stoped after 4-5 year

float.

archimedes' principle

denser than water sinks in water.

denser than mercury would sink in it

one "light year" is the distance that light travels, through vacuum, in one julian year.   that's 365.25 days, of 24 hours each.