A cloud collapses to form a star and disk. Planets form from this disk. According to our current understanding, a star and its planets form out of a collapsing cloud of dust and gas within a larger cloud called a nebula.
The Earth is thought to have been formed about 4.6 billion years ago by collisions in the giant disc-shaped cloud of material that also formed the Sun. Gravity slowly gathered this gas and dust together into clumps that became asteroids and small early planets called planetesimals.
Explanation:
Arid climate -
The most district defining character of an arid climate is the lack of moisture. The air and soil is dry and therefore the yearly precipitation is very low. Arid climate can be of two types, warm and cold arid climates. These are mostly deserts, due to lack of soil moisture
The distribution of this climate type is found along the 30 degree latitude line, both in Northern and Southern Hemisphere.. The polar climate is also arid in nature .