PLEASE HELP! The diagrams show two models.

Which statement best describes both models?

A. Model X is the heliocentric model in which Earth is the center of the solar system; model Y is the geocentric model in which the Sun is the center of the solar system.

B. Model X is the geocentric model in which the Sun is the center of the solar system; model Y is the heliocentric model in which Earth is the center of the solar system.

C. Model X is the heliocentric model in which the Sun is the center of the solar system; model Y is the geocentric model in which Earth is the center of the solar system.

D. Model X is the geocentric model in which Earth is the center of the solar system; model Y is the heliocentric model in which the Sun is the center of the solar system.

Answer D

Explanation:

Heliocentric is the model we use today, where we all revolve around the sun. Geocentric was a model that was long ago discarded after the discovery of telescopes.

a 20-cm-long, cylindrical graphite (pure carbon) rod is inserted into an oxidizing atmosphere at 1145 k and 1.013 x 105 pa pressure. the oxidizing process is limited by the diffu- sion of oxygen counterflow to the carbon monoxide that is formed on the cylindrical surface.

substituting a hydrogen atom with a halogen in a hydrocarbon:

- the single bond remains single. a is wrong.

- the bond with hydrogen is as strong as with a halogen. c is wrong

- a hydrocarbon is saturated if there is no double bond. we do not know that so d is wrong.

- carbon will always have four valence electrons. e is wrong.

by elimination, the correct answer is b. the boiling point of the new compound increases.