In the video on the effect of exercise on cells, it was pointed out that people who exercised regularly had younger cells. The researchers looked for a marker in volunteer's blood. They found "strands" and surmised that, "the longer these strands, the younger the cells".

1. What are the "strands" mentioned in the video?

2. Based on what you learned in this course, explain the relationship between longer "strands" and "younger cells".

3. The video also suggested that exercise reduces inflammation and stress. Paradoxically, increased exercise increases aerobic respiration of cells which creates oxidizing agents known as oxygen free radicals. These oxygen radicals have been linked to diseases of aging including inflammation. EXPLAIN this apparent paradox; in other words, how do you reconcile the apparent discrepancy between these two opposing observations.