Answer:
Closed Systems. The earth system as a whole is a closed system. ... Virtually no mass is exchanged between the Earth system and the rest of the universe (except for an occasional meteorite). However, energy in the form of solar radiation passes from the Sun, through the atmosphere to the surface.
Explanation:
PCR allows for the analysis of DNA fragments through the comparison of the base pairs each molecule contains, which can then be used for genetic screening and the identification of individuals and DNA fragments
The Best Answer :
<span>"G2 phase is the third, final, and usually the shortest subphase during interphase within the cell cycle in which the cell undergoes a period of rapid growth to prepare for mitosis. It follows successful completion of DNA synthesis and chromosomal replication during the S phase, and occurs during a period of often four to five hours. This far into interphase the nucleus is well defined, bound by a nuclear envelope and contains at least one nucleolus. Although chromosomes have been replicated they cannot yet be distinguished individually because they are still in the form of loosely packed chromatin fibers. The G2 phase prepares the cell for mitosis (M phase) which is initiated by prophase.
At the end of this gap phase is a control checkpoint (G2 checkpoint) to determine if the cell can proceed to enter M phase and divide. The G2 checkpoint prevents cells from entering mitosis with DNA damaged since the last division, providing an opportunity for DNA repair and stopping the proliferation of damaged cells. Because the G2 checkpoint helps to maintain genomic stability, it is an important focus in understanding the molecular causes of cancer."</span>
