  It takes a mallard duck 28-30 days for the eggs to hatch. All of the eggs will hatch within 24 hours and they will then head for water.Never to return to the nest. 3 people found this useful. It takes a mallard duck 28-30 days for the eggs to hatch. All of the eggs will hatch within 24 hours and they will then head for water. Never to return to the nest. 3 people found this useful.
The two main causes of strokes are termed ischemic and hemorrhagic and involve blood vessels in the brain. Ischemic strokes comprise about 80% to 85% of all strokes. With an ischemic stroke, a blood vessel in the brain becomes clogged with a clot just like the clogged arteries in the heart. With a hemorrhagic stroke, a blood vessel in the brain actually bursts or leaks. Hemorrhagic strokes tend to be more serious.
What Causes a Stroke. A common cause of stroke is atherosclerosis -- hardening of the arteries. Plaque made of fat, cholesterol, calcium, and other substances builds up in the arteries, leaving less space for blood to flow. A blood clot may lodge in this narrow space and cause an ischemic stroke. Atherosclerosis also makes it easier for a clot to form.