the oldest fossils on earth are 3.5 billion years
Wait… what do you need help with lol
Since you didn't have any extra information about the question I'll be presenting an example from my own textbooks that I've used.
An example of a direct observation is listening to a cricket chirp at night, and counting the number of chirps per minute.
Direct Observation is where the evaulator watches the subject in their usual habitat without disrupting or altering it.
Step by step solution: The position of hydrogen is controversial in the periodic table because hydrogen is the only element without neutrons. Hydrogen is a nonmetal and is placed above the group in the periodic table because it has ns1 electron configuration like the alkali metals.
