Question

which phenomenon/idea did arthur holmes believe was responsible for continental drift?
moon phases
earths revolution
thermal convection
coriolis effect

Explanation:

Arthur Holmes proposed that thermal convection currents in the Earth's mantle were responsible for continental drift. Moon phases relate to lunar cycles, Earth’s revolution is its orbit around the Sun, and the Coriolis Effect affects moving objects on a rotating Earth—none explain continental drift as Holmes proposed thermal convection.

Answer:

Thermal Convection (the option with "Thermal Convection")