Question

during the pleistocene epoch (the last two million years), scientists have documented frequent and dramatic temperature swings that are likely due to:

subtle shifts in the earths rotation and changes in cloud cover

changes in the solar radiation from the sun

changes in the earths gravitational pull

frequent asteroid strikes

rapid shifts in the anthropogenic emissions globally

Explanation:

During the Pleistocene Epoch, Milankovitch cycles (subtle shifts in Earth's rotation and orbit) and changes in cloud - cover influenced climate. Solar radiation changes are less significant on this timescale, Earth's gravitational pull doesn't cause such temperature swings, asteroid strikes are rare, and anthropogenic emissions were negligible then.

Answer:

Subtle shifts in the earth's rotation and changes in cloud cover