What are Braxton Hicks contractions? Braxton Hicks contractions can begin as early as the second trimester. However, they are most commonly experienced in the third trimester. When this happens, the muscles of the uterus tighten for approximately 30 to 60 seconds, and sometimes as long as two minutes.
Main articles: Hydrology and Water distribution on Earth. Water covers 71% of the Earth's surface; the oceans contain 96.5% of the Earth's water. The Antarctic ice sheet, which contains 61% of all fresh water on Earth, is visible at the bottom. Condensed atmospheric water can be seen as clouds, contributing to the Earth's albedo.
Front and back of the earth. The blue area represents water. As oceans are very wide and there are multiple to be found on earth, oceans store most of the earth's water. This is apparently 97% of the total amount of water on earth, 2% of which is frozen. Of all the water on earth, which is 97,14% of the total amount of surface water, only 2,59% is freshwater. Of this 2,59% another percentage is trapped in ice caps and glaciers, which is about 2%.