The half-life of a radioisotope is the amon the symbol 42He, the subscript 2 is the mass number for helium and the superscript 4 is the atomic number for helium.
Answer:Petroleum, also called crude oil, is a fossil fuel. Like coal and natural gas, petroleum was formed from the remains of ancient marine organisms, such as plants, algae, and bacteria. Over millions of years of intense heat and pressure, these organic remains (fossils) transformed into carbon-rich substances we rely on as raw materials for fuel and a wide variety of products.
Explanation:
True-breeding plants have offspring with the same traits when they are self-fertilized.
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