Bằng phương pháp hóa học hãy nhận biết các chất khí không màu trong 4 lọ không nhãn gồm:CO, O2,H2,CO2

Determine the wavelength of the light absorbed when an electron in a hydrogen atom makes a transition from an orbital in the n=3 level to an orbital in the n=7 level.

The organism shown is a free-living one that is anchored to the bottom of ponds and streams during one stage of its life cycle what is the common name for the group to which this organism belong

Why are people not able to skip a dive to the deepest part of the ocean