Explain how to identify a starting point on a line? P. S this is for 8th grade science on edge

Explain why scientists use shared characteristics to make cladograms.

Let the ed50 of a recreational drug be defined as the amount required for 50% of a test group to feel high or get a buzz. if the ed50 value of ethanol is 470 mg/kg body mass, what dose would a 70 kg party goer need to quickly consume in order to have a 50% chance of getting a buzz? 235 mg 470 mg 32,900 mg 35,000,000 mg

What 3 categories are elements divided