Which of the following is an example of biological weathering?
a. plant roots growing through rock
b. water freezing in the cracks of rocks
c. oxygen reacting with the minerals in rock
d. rocks breaking from thermal expansion
frost wedging weathers rock because
water expands when it freezes
oxygen expands when it is heated
water contracts when it freezes
plant roots create external pressure

Which statements describe sustainable development? multiple answer choice -fishing does not remove more fish from water systems than can be replaced by the number of fish that will be born to replace them. -sustainable development is development that is designed to improve the economic conditions in less-developed countries. -sustainable development is mainly a regional issue. -sustainable development means water is used at a rate that won't reduce the amount available for future use. - sustainable development policies only need to be concerned with environmental protection. - trees cannot be cut down faster than the number that will be replaced by new growth.