Are roots or plant growth making cracks in concrete chemical or mechanical weathering?

it is technically biological weathering but mechanical works as well

the dissolution of polymer can be thermodynamically described in 2 steps.

warm front forms when a moist, warm air mass slides up and over a cold air mass. as the warm air mass rises, it condenses into a broad area of clouds. a warm front brings gentle rain or light snow, followed by warmer, milder weather.

hope i !