Consider the following statements:

1.Shield volcanoes are mostly made up of basalt, a type of lava that is more viscous when erupted.

2.Shield volcanoes are steep and are characterized by low explosivity.

3.Composite volcanoes are characterized by eruptions of cooler and more viscous lavas.

4.Composite volcanoes often result in explosive eruptions.

Which of the statements given above is/are correct?