Option 1 states that the forces of diastrophism may be slow and gradual, to the extent that they go unnoticed for a long period of time. Diastrophism refers to the deformation or changes that occur in the Earth`s crust due to tectonic forces. These forces may cause the uplift, folding, or sinking of rock layers, leading to the formation of mountains, valleys, and other geological features.

The correct answer is option 1 because it accurately describes the nature of diastrophism. These forces can act over long periods of time, often thousands or millions of years, resulting in gradual changes in the Earth`s surface. In many cases, these changes are not immediately noticeable to humans as they occur slowly and gradually. However, over time, the effects of diastrophism become evident as we observe the formation of new landforms or the modification of existing ones.

Option 2 is incorrect because it suggests that the forces of diastrophism can also be sudden, which is not typically the case. Option 3 is also incorrect as it suggests that the forces may be sudden and so fast that they go unnoticed for a long period of time, which contradicts the gradual nature of diastrophism. Option 4 is incorrect because