Human genes can combine in about different combinations.

The population of unionid mussels decreased after zebra mussels were introduced. zebra mussels competed with the unionid mussels for food. the zebra mussels were able to displace the unionid mussels, allowing the zebra mussel population to increase  over the years. the unionid mussel population decreased because  of lack of food.

First adhesives: hide glue.  which is made by boiling raw hides and bones or fish skins and bladders.other first adhesives: asphalt/tar, pitch/plant sap, and even blood.hope that : )