Fill in the Blanks Areas of science Online version Complete the sentences with the right words. by Oxana Sidorova 1 orbit velocity system particle elementary cell Gravity organs system variable universe compound molecule chemical species solar coordinate elements equation ASTRONOMY 1 . The Sun and the planets orbiting it make up the . 2 . The Moon makes one complete around the Earth in approximately 27 . 3 days . 3 . It was discovered in the 20th century that the is expanding . BIOLOGY 1 . The smallest organisms consist of one . 2 . there approximately one million known of insects of earth . 3 . in the last Biology lesson , we had to draw and label various internal : the liver , kidneys , and so on . CHEMISTRY 1 . Maria Sklodowska - Curie discovered the polonium and radium . 2 . In 1785 Antoine Lavoisier demonstrated that water is a of hydrogen and oxygen . 3 . A of hydrochloric acid consists of one atom of hydrogen and one of chlorine . MATHEMATICS 1 . In secondary school we learned to solve quadratic - at least some of us did . 2 . In the expression ax2 + bx + c , a , b , and c are coefficients and x is the . 3 . The Cartesian allows you to describe every point on a plane using a pair of numbers . PHYSICS 1 . is the force with which objects with mass attract one another , described by Newton . 2 . The of light is constant ; it's value is 299 , 752 , 458 metres per second . 3 . The electron is an with a negative charge .
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