In English conditional sentences, the condition clause (protasis) is a dependent clause, most commonly introduced by the conjunction if. Other conjunctions or equivalent expressions may also be used, such as unless (meaning if...not), provided (that) , providing (that) and as long as.irst conditional or conditional I refers to a pattern used in predictive conditional sentences, i.e. those that concern consequences of a probable future event (see Types of conditional sentence).
Weathering and erosion. Weathering is the process where rock is dissolved, worn away or broken down into smaller and smaller pieces. There are mechanical, chemical and organic weathering processes. Organic weathering happens when plants break up rocks with their growing roots or plant acids help dissolve rock.
force is often strong enough to split the rock. This process, called root wedging, is a kind of physical weathering (Figure 11.7). However, roots also produce enzymes that attack rock minerals. So root wedging is really a combination of physical and chemical weathering. Rockfalls Falling rock can break into very small pieces when it hits the ground. The graphic below shows an example of rocks (and trees!) affected by falling rock. Rockfalls can occur when a big chunk of rock is split off of a large landform by frost wedging or root wedging. Rockfalls speed up the weathering process by quickly