THe number of chromosomes in a nucleus depends on the species. In humans each nucleus has 23 pairs of chromosomes so there are 46 chromosomes total.
On average, a garage door opener should last about 10 â 15 years. Some last longer and some last a shorter amount of time, but keeping up with maintenance can help increase the lifespan.If moving parts arenât lubricated, the door isnât balanced correctly, etc., the opener tends to wear out more quickly.he best thing you can do to ensure your garage door opener lasts as long as possible is to keep up with professional maintenance. This typically includes: 1  Visual inspection of the springs, rollers, cables, track and pulleys. 2  Lubrication of moving parts to ensure smooth operation. 3  Door balance.
1 When you intend to replace your garage door spring, take into consideration the longevity of the springs. 2  The life span of a spring having 5,000 or 10,000 cycles of expected wear, will last only about five years to seven years. 3  Choose the appropriate spring that complements the size and weight of your garage door. On average, to have your springs replaced on your garage door will vary in cost anywhere from $110 to as much as $200 per spring. 2  To get an exact quote, consider using free websites such as HomeAdvisor.com.