All above
Severe Droughts can make land unlivable, as all living things need food and water to survive
That would be the proton. The number of protons in the nucleus determine which element it is and its properties.
When using filter paper chromatography to separate ink, one will observe that more colours are mixed into darker inks. The darker an ink is, the more the colours that will be separated out during chromatography process. Thus, the observation that the darker the ink, the more colours are mixed into it will lead one to believe that ink is a mixture.
It will always produce a near-exact measurement
