TASK DEFINITION: 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.
PROBLEM: Fact 1: a glacier causes mechanical weathering. 
Fact 2: Mechanical weathering produces detritus.

SOLUTION: A glacier can produce detritus.

PROBLEM: Fact 1: Most species go through larval stages after hatching. 
Fact 2: Geckos hatch from eggs.

SOLUTION: Geckos go through larval stages while growing.

PROBLEM: Fact 1: Scientists still know relatively little about Archaea. 
Fact 2: Bacteria and archaea are the only prokaryotes.

SOLUTION:
Scientists still know relatively little about prokaryotes.