Elements can combine to form molecules, like O2 or CO2. Elements combine to form molecules and these elements are joined together by

A.)chemical bonds

B.)nuclear energy

C.)sharing nuclei

D.)attractive forces

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 :