The respiratory system includes a layer of cells in the air passages that clean the air before it gets to the lungs. this layer of cells is best classified as ) an organ system(2) an organ (3) an organelle(4) a tissue

4) a tissue

Explanation:

When a group of cells come together to perform a specified function, they are referred to as tissue. When a group of tissues come together to perform a specified function, they become an organ. If a group of organs, come together to perform a specific function, they are referred to as a System.

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explanation:

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the correct answer is: b. pantala flavescens, because these organisms would have a high level of genetic variation due to sexual reproduction.  

because involves two organisms (parents) whose genetic material combines, sexual reproduction leads to genetic variation in new generations of offspring. the offspring is an unique organism, with new genome, more protected with the higher ability to adapted. this process is fundamental to evolution.