Answer:
The cooling of the planet, followed by creation of oceans, the appearance of plants, oxygen production and sea animals led to the first land animals.
Step-by-step explanation:
According to the text the following causal chain led to the beginning of life on Earth.
1) Cause: Gradual cooling of the surface.
2) Effect: Formation of a hard crust on surface.
3) Cause: Hot gases and liquid rock from inside broke through the crust in different locations.
4) Effect: Formation of mountains, deep trenches and ocean beds.
5) Cause: Cooling of atmosphere.
6) Effect: Formation of oceans of violent storms and rains due to condensation of the water vapour.
7) Cause: Appearance of plants.
8) Effect: Appearance of sea animals due to the production of photosynthetic oxygen.
9) Cause: Sea animals become bigger.
10) Effect: First animals that crawled on to the land.
According to this, the cooling of the planet, followed by creation of oceans, the appearance of plants, oxygen production and sea animals led to the first land animals.