A gene is a segment of a _ & is made of _. Each gene codes for the production of one _ & each protein determines one _. Every 3 _ is called a codon and codes for a different _ acid. A string of amino acids make a _.

the population of unionid mussels in the hudson river decreased after zebra mussels were introduced. zebra mussels, a nonnative species, competed with the unionid mussels for food. the zebra mussels were able to outcompete the unionid mussels, allowing the zebra mussel population to increase dramatically over six years. the unionid mussel population decreased due to a lack of food.

hope this :