Scientists think that convection currents flow in earth’s a. continents. b. mantle. c. lithosphere. d. inner core.

Your answer would be b, mantle.

Convection currents is the flow which happens because cooler liquid is denser and hotter is less dense. This means the cooler liquid sinks, then gets hotter (as it is therefore then closer to the hot core), rises, then gets cooler, and then repeat.

This can only really happen with liquids or gases, as solids can't exactly flow. Therefore, it cannot be a, continents, c, lithosphere (the outside solid layer of the Earth), or d, inner core (as surprisingly, the inner core is solid)

Therefore, your answer is b, the mantle.