This statement is true: <span>The mineral ores for gold and silver are commonly found in the earth's crust.
These two types of metals are known as native metals because they are naturally occurring within the Earth's stratosphere. These metals are usually found through mining processes because they are often found mixed with sediments and other soil components. One method of acquiring gold is called gold panning while silver is obtained mixed with silver sulfide and sulfosalt minerals.</span>
Answer:
The answer is A. Invented SCUBA
Explanation:
- Emile Gagnan and Jacques Cousteau were engineers who invented the first SCUBA device, the Aqua-Lung.
- Gagnan's most important contribution to this discovery was his theory that a valve commonly used in gas generator engines would be useful in regulating air supply under water in varying pressures.
The right answer is <span>the light saturation point.
More light usually results in higher photosynthesis levels. However, with the increase of the intensity of the light, the photosynthesis rate eventually reaches a maximum point. This point is called "luminous saturation point".
When this point is reached, the intensity of the light does not increase the rate of photosynthesis and the rate of photosynthesis curve ceases to increase.
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Exchange of gases in fish is very efficient because of: the large surface area of the gills. the large surface area of the blood capillaries in each gill filament. the short distance required for diffusion – the outer layer of the gill filaments and the capillary walls are just one cell thick.
Answer:
The correct ansqwer is- Vitamin D
Explanation:
Vitamin D is the vitamin that can be synthesized by the human body itself therefore it is not an essential vitamin for human beings. Human skin is the part that helps in making this vitamin in humans.
The natural form of vitamin D is vitamin D3 which is formed by the sunlight exposure on the skin. When we expose our skin in the sunlight the UV radiation penetrated our skin and converts provitamin D3 into pre-vitamin D3 then this previtamin can be isomerized into the natural form of vitamin D Which is vitamin D3. So the right answer is vitamin D.
