phagocytotic cells such as macrophages identify a variety of enemies by recognizing markers unique to pathogens. they would be classified as which type of defense system?

Which group of chordates does  notpossess true backbones?                 a.  birds      b.  frogs and toads      c.  lampreys      d.  crocodilians

When does the circulatory system work with the respiratory system? a. during blood cell formation b. during cellular respiration c. during intestinal digestion d. during a viral infection

What would most likely happen if a person increased the amount of saturated fat in his or her diet? the person's risk of cardiovascular disease would increase. the person's risk of cardiovascular disease would decrease. the person's bad cholesterol would decrease. the person’s good cholesterol would increase.