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: Some viruses have an envelope of phospholipids and proteins. 
Fact 2: Viruses are enveloped by similar membranes.
viruses have similar membranes.

Fact 1: if seeds stick to the fur of an animal then that seed will be transported by the animal. 
Fact 2: Along with the wind, birds are the primary transporters of berries and seed.
Birds can carry seeds in their feathers.

Fact 1: Flatworms belong to the phylum Platyhelminthes. 
Fact 2: Most of the flatworms are parasitic, although the Turbellaria are free-living in fresh water.

Phylum Platyhelminthes are mostly parasitic.