Combine the given two facts to write a concluding fact. Note that there should be some parts of the first and second facts that are not mentioned in this conclusion fact. Your combined fact should be the result of a chain between the two facts. Chains form when two facts connect together to produce a concluding fact. An example of a chain is: "pesticides cause pollution" (fact1) + "pollution can harm animals" (fact2) → "pesticides can harm animals" (conclusion fact). Parts of the concluding fact overlap with the first and the second fact. To construct such a  concluding fact, a useful way is to borrow the subject from one fact and the ending conclusions from another fact.

Fact 1: if a planet becomes too hot then that planet cannot sustain life. 
Fact 2: Life depends to a large degree on the temperature of the planet, and temperature depends in part on the distance of the planet from the sun.
Life cannot be sustained above a certain temperature.

Fact 1: when a river floods , that river deposits soil in flood plains. 
Fact 2: Soil erosion harms farm and grazing lands and increases flooding and desertification.
When a river floods, that river harms farm and grazing lands.

Fact 1: if fossils of a water animal or plant are found in a place then that place used to be covered by water in the past. 
Fact 2: Graptolites , in deep-water deposits, are the dominant fossils.

if graptolites are found in a place then that place used to be covered by water.