Which of the following is an example of biological weathering

An example of biological weathering is the widening of gaps in rocks caused by tree roots since pressure or stress is exerted on the rocks due to the growing plant roots. The pressure is exerted by a biological process (i.e., growing roots), even though the process is physical.

Plants and animals and its action speeds up mechanical and or chemical weathering, which in turn causes biological weathering.

With the help of the chemicals that are produced by the tiniest bacteria, algae and liches, the rocks which they live in are also broken down by them in order to get the nutrients they need.