Jesse has been working to improve his cardiovascular fitness. Which of the following is the BEST objective measure of his progress? 1. He feels proud of what he has accomplished so far.

2. He has lost enough weight that he needs to buy pants with a smaller waist.

3. He can run a mile five minutes faster than he could when he started.

4. He seldom has problems with muscles strain or joint pain nowadays.

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.