zebra mussels can live six or seven years, now it seemed that most were dying after only one or two years. Since
Because
Although
For example

Why is mme. loisel "full of anxiety" when she asks to borrow the necklace? a. she is humiliated at having to borrow the necklace. b. she dreads going to the reception. c. she lacks confidence in her beauty. d. mme. forester gives her too many pieces to choose from