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Hydrogen is the chemical element with the symbol H and atomic number 1. With a standard atomic weight of 1.008, hydrogen is the lightest element in the periodic table.

Explanation

Angstrom , unit of length used chiefly in measuring wavelengths of light, equal to 10−10 metre, or 0.1 nanometer.

It is named for the 19th-century Swedish physicist Anders Jonas Ångström.

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Explanation

Braun was a German-born American aerospace engineer and space architect. 

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The noun discovery means the finding or uncovering of something.

Explanation

Electricity would remain little more than an intellectual curiosity for millennia until 1600, when the English scientist William Gilbert wrote De Magnete, in which he made a careful study of electricity and magnetism, distinguishing the lodestone effect from static electricity produced by rubbing amber.

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The stamen is the male reproductive organ.

It consists of a pollen anther and a long supporting filament.

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Explanation

Rust diseases of wheat, the most common these days is called leaf or brown rust and is caused by P. triticina Eriks.

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Oxygen is necessary for combustion.