when the author claims that people need the right number of calories, what can you infer about the meaning of that phrase?

Health and cardio respiratory fitness occurs when the heart is working, at minimum, 50 percent of heart rate reserve. true or false

What is the main structural difference between enveloped and nonenveloped viruses? a) enveloped viruses have their genetic material enclosed by a layer made only of protein.b) nonenveloped viruses have only a phospholipid membrane, while enveloped viruses have two membranes, the other one being a protein capsid.c) enveloped viruses have a phospholipid membrane outside their capsid, whereas nonenveloped viruses do not have a phospholipid membrane.d) both types of viruses have a capsid and phospholipid membrane; but in the nonenveloped virus the genetic material is between these two membranes, while in the enveloped virus the genetic material is inside both membranes.

How does stress affect the digestive system? o a. reduces ability to break down foods b. reduces acid production to slow digestion o c. increases desire for fruits and vegetables o d. increases ability to break down food submit