It is B, <span>In fact, water will sink as it cools until a certain point. If I recall correctly this is around 39 F. As the temp gets lower than that water actually begins to expand and becomes less dense. This is why ice floats, which we should all be thankful for. If ice didn't float than all water on earth would likely freeze solid and life would have probably never evolved past small single celled things.</span>
<span>D) European exploration and colonization of the Americas, Africa, and Asia.</span>
Answer:
2. the line separating Australian animal species from non-Australian species
Explanation:
The Wallace line is an animal boundary line drawn by Alfred Wallace that separates Australian fauna species from non-Australian fauna species. It's a transitional zone between Austrialia and the Asia continent. The animals found in south East Asia is so much different from those found in Australia, hence the line drawn. The line is just one of the many biogeographical borders in the world separating geographical regions with not so similar group of plants and animals.
With earths core being very very hot it is plasma which is lava but its comes closer to the surface and cools downs to become a solid.
Answer: Ozone is considered as chief polluting gas.
Explanation:
The ozone is a ground level pollutant. It is a colorless gas. It causes irritation in the eyes and respiratory tract. It is one of the components of smog as it causes pollution in the atmosphere. It is produced by the two primary pollutants that are nitrogen oxides and volatile organic compounds when they react with the sunlight. The ozone makes the air irrespirable. It is the main cause of throat irritation, labored breath, pain in chest and also responsible for respiratory diseases. It reduces the body's ability against infection. The ozone depleting substances like aerosol, chlorofluorocarbon are widening the ozone depleting zone as halides present in these substances react with the ozone causing depletion. This allows the entry of harmful ultraviolet radiation penetrating the atmospheric layers.
