How does a scientist explain something when a controlled experiment cannot be carried out

Which statements indicate what the fossil record suggests about evolution on Earth? Check all that apply. Humans have only recently existed on Earth. Organisms originally lived only in Earth's water. Life on Earth started when water formed on Earth.

Briefly define weather, season and Climate.

NF3 has three F atoms bonded to a central N atom, with one lone electron pair on the N. What is the shape of this molecule?

A 16.0 mL sample of a 1.04 M potassium sulfate solution is mixed with 14.3 mL of a 0.880 M barium nitrate solution and this precipitation reaction occurs: K 2 S O 4 (aq) + Ba (N O 3) 2 (aq) →BaS O 4 (s) + 2KN O 3 (aq) The solid BaS O 4 is collected,

What is the classification for this polynomial 3g^2?

Have scientists found any reliable predictors for earthquakes, like radon gas release or weird animal behavior?

The table compares the characteristics of a substance in three different states of matter. Comparison of Characteristics Characteristic State X State Y State Z Average Kinetic Energy of the Molecules Low Greatest Least Particle Attraction/Forces

In an exothermic reaction the bonding energy of the product is?

How many molecules are contained in two 540.-mg tablets of penicillin (C16H18N2O4S, molar mass 334.4 g/mol) ? Report your answer with the appropriate number of significant figures.

What was the result of john Brown's raid on Harpers ferry