Which of the following describes the contribution of eratosthenes? a. discovery of the geocentric theory b. discovery of a mathematical formula to relate the sides of a right triangle c. calculation of the circumference of the world to within one percent d. calculation of the weight of ships by the amount of water they displaced

The correct answer is option C, calculation of the circumference of the world to within one percent.

Eratosthenes was a mathematician and astronomer from ancient Greece. He calculated the circumference of the Earth with reasonable accuracy by noting the position of the Sun’s rays in two different locations.

Eratosthenes believed the Earth was a sphere and used trigonometry and geometry to calculate the distance around Earth.

the correct answer is boyle

explanation:

the largest database of organic compounds lists about 10 million substances, which include compounds originating from living organisms and those synthesized by chemists. the number of potential organic compounds has been estimated at 1060—an astronomically high number. the existence of so many organic molecules is a consequence of the ability of carbon atoms to form up to four strong bonds to other carbon atoms, resulting in chains and rings of many different sizes, shapes, and complexities. the simplest organic compounds contain only the elements carbon and hydrogen, and are called hydrocarbons. even though they are composed of only two types of atoms, there is a wide variety of hydrocarbons because they may consist of varying lengths of chains, branched chains, and rings of carbon atoms, or combinations of these structures. in addition, hydrocarbons may differ in the types of carbon-carbon bonds present in their molecules. many hydrocarbons are found in plants, animals, and their fossils; other hydrocarbons have been prepared in the laboratory. we use hydrocarbons every day, mainly as fuels, such as natural gas, acetylene, propane, butane, and the principal components of gasoline, diesel fuel, and heating oil. the familiar plastics polyethylene, polypropylene, and polystyrene are also hydrocarbons. we can distinguish several types of hydrocarbons by differences in the bonding between carbon atoms. this leads to differences in geometries and in the hybridization of the carbon orbitals.