HUMAN ACTIVITIES ARE threatening the health of the world's oceans. More than 80 percent of marine pollution comes from land-based activities. From coral bleaching to sea level rise, entire marine ecosystems are rapidly changing.
Global warming is causing sea levels to rise, threatening coastal population centers. Many pesticides and nutrients used in agriculture end up in the coastal waters, resulting in oxygen depletion that kills marine plants and shellfish. Factories and industrial plants discharge sewage and other runoff into the oceans. Oil spills pollute the oceans, though U.S. water-sewage treatment plants discharge twice as much oil each year as tanker spills. Air pollution is responsible for almost one-third of the toxic contaminants and nutrients that enter coastal areas and oceans. The United Nations Food and Agriculture Organization estimates that 31.4 percent of fish stocks are either fished to capacity or over-fished.
<span>Charles Darwin and Alfred Russel Wallace were the ones who had the idea of evolution in 1858!</span>
Answer:
72km/hr
Explanation:
Speed in Km is usually represented in hours. so if the car is in constant velocity, and if the car travels 36km in 30 min then it travels 72km in 1 hour.
so the speed of the car is 72km/hr
+1
An electron has a negative charge so losing a charge of -1 from an uncharged, or neutral, atom will leave an ion with a positive charge.
Answer:
Our atmosphere has five different layers. They are:
1. Troposphere: This is the most important layer of the atmosphere with an average height of 13 km from the earth. It is in this layer that we find the air that we breathe. Almost all the weather phenomena such as rainfall, fog and hailstorm occur here.
2. Stratosphere: This layer extends up to a height of 50 km. It presents the most ideal condition for flying airplanes. It contains a layer of ozone gas which protects us from the harmful effect of the sun rays.
3. Mesosphere: This layer extends up to a height of 80 km. Meteorites bum up in this layer on entering from the space.
4. Thermosphere: In this layer, the temperature rises very rapidly with increasing height. The ionosphere is a part of this layer. It extends between 80-400 km. This layer helps in radio transmission. Radio waves transmitted from the earth the reflected back to the earth by this layer.
5. Exosphere: It is the uppermost layer where there is very thin air. Light gases such as helium and hydrogen float into space from here.
