During sleep, your brain’s electrical activity goes through a five-phase cycle. A short afternoon catnap of 20 minutes yields mostly Stage 2 sleep, which enhances alertness and concentration, elevates mood, and sharpens motor skills. To boost alertness on waking, you can drink a cup of coffee before you nap.
Like humans, dogs have two sets of teeth in their lives. The 28 baby teeth erupt through the gums between the third and sixth weeks of age. Puppies do not have to grind much food, so they do not have molars. Puppy teeth begin to shed and be replaced by permanent adult teeth at about four months of age.