Question

an earthworm kept on a glass tile was not able to move why

Answer 1

Earthworms have microscopic hairs or bristles all over their body which provide the necessary traction while movement. These bristles or setae are present on each segment of their body and it imparts the necessary grip or anchorage for forward and backward movement.

Glass is smooth in nature so earthworms cannot move as the setae will not get sufficient surface support to move the body.