Which of the following statements are true regarding Kober's theory of mountain building?

1. Kober proposed the geosynclinal theory, which suggests that mountains form from large depressions on the Earth's crust that fill with sediments and are eventually uplifted to form mountain ranges.

2. According to Kober, the primary mechanism for mountain building involves the contraction of the Earth's crust due to cooling, leading to folding and faulting of geosynclinal deposits.

3. Kober's theory emphasizes the role of volcanic activity in directly lifting up the mountain ranges without the involvement of sediment deposition in geosynclines.

4. He suggested that the process of mountain building is relatively quick, occurring in a few million years as opposed to tens of millions of years.