Question

where do scientists find the evidence about past atmospheric conditions in ice cores? through the composition of ancient snow all these are correct by measuring the thickness of each layer air bubbles trapped in ancient ice

Explanation:

The composition of ancient snow can reveal the chemical makeup of past atmospheres. Measuring layer - thickness can give information about precipitation and climate conditions at the time of snowfall. Air bubbles trapped in ancient ice contain samples of the past atmosphere.

Answer:

B. All these are correct