Explanation:
Tarbuck, Earth's crust is made up of several elements: oxygen, 46.6 percent by weight; silicon, 27.7 percent; aluminum, 8.1 percent; iron, 5 percent; calcium, 3.6 percent; sodium, 2.8 percent, potassium, 2.6 percent, and magnesium, 2.1 percent
About 29% of Earth's surface is land consisting of continents and islands. The remaining 71% is covered with water, mostly by oceans but also lakes, rivers and other fresh water, which all together constitute the hydrosphere.
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Earth.
Almost 99% of the minerals making up the Earth's crust are made up of just eight elements. Most of these elements are found combined with other elements as compounds.
What do you need examples of?
Formed when lightning struck water i believe
Answer:
Chlorophyll is a green pigment found in chloroplast in plants. It absorbs sunlight during the process of photosynthesis. It is a chelate molecule. In a chelate molecule a central metal ion forms bonds with a large organic molecule made of carbon, hydrogen and other elements like nitrogen or oxygen.
In chlorophyll, magnesium is the central metal ion and it is bonded to a large organic molecule called as porphyrin. Porphyrin constitutes four nitrogen atoms to which the central magnesium is bonded in square planar arrangement. Since chlorophyll is responsible for the green color of the leaves, more the green color more the chlorophyll content and more is the nitrogen content. Hence, chlorophyll meter measures this green light and finds out if the plant needs more or less nitrogen.
