show more 26wks1dy pregnant. Why is it that in a singleton pregnancy, full term is considered 37wks, however in a twin pregnancy, full term is considered 35wks, & in a triplet pregnancy, full term is considered 31wks? Don't the babies in all pregnancies grow/develop at the same rate?hy is it that in a singleton pregnancy, full term is considered 37wks, however in a twin pregnancy, full term is considered 35wks, & in a triplet pregnancy, full term is considered 31wks?
For orbits around the Earth, see Geocentric orbit. In astronomy, the geocentric model (also known as geocentrism, or the Ptolemaic system) is a superseded description of the universe with the Earth at the center. Under the geocentric model, the Sun, Moon, stars, and planets all circled Earth.
The Difference is that a heliocentric model says that the sun is in the center but not the exact center and all the other planets and the moon orbit the sun. But a geocentric model states that the earth was in the center and that the sun moon and stars all went around earth. That is the difference. Heliocentric: