Answer:
Retrograde Motion
Explanation:
Geocentric model of planets was proposed by Ptolemy. It stated that all sun, planets and stars revolve round the earth in circular orbits.
NOTE: Ptolemy: an ancient astronomer, geographer, and mathematician who considered the Earth the center of the universe (the "Ptolemaic system").
A solution of KNO3 consists of ions of potassium and nitrate. The ionic equation is expressed as:
KNO3 = K+ + NO3-
There is 1 is to 1 ratio between the substances. So, the molarity of NO3- in the solution is calculated as follows:
0.160 mol / L KNO3 ( 1 mol NO3- / 1 mol KNO3 ) = 0.160 M NO3-
Talc is not a good choice when building a statue because the mineral Talc is one of the weakest minerals on the Mohs Scale with a hardness of 1 since it could be scratched by a fingernail, which means that when people build a statue with Talc, it could be easily broken down.
Answer:
Chitin
Explanation:
A fly's main body is made of a thorax and an abdomen. These parts are covered by a hard exoskeleton made of a bony substance called chitin.