Answer:
1. Answer: Light can travel in a vacuum, and its speed is constant if the source is moving or stationary.
Light travels at constant speed in vacuum even if the source is moving or stationary. If the source is moving, the apparent frequency/ wavelength changes.
40%-THE HEIGHT WITH DISTILLED WATER WAS 25, WHILE WITH A PH OF 2 IT WAS 15, THEREFORE A 40% REDUCTION IN HEIGHT WAS OBSERVED.
I think it's struthio cameleus.. something like that