Answer:
Chromosomes were first named by cytologists viewing dividing cells through a microscope. The modern definition of a chromosome now includes the function of heredity and the chemical composition. A chromosome is a DNA molecule that carries all or part of the hereditary information of an organism. In eukaryotic cells, the DNA is packaged with proteins in the nucleus, and varies in structure and appearance at different parts of the cell cycle.
Explanation:
Cells reproduce genetically identical copies of themselves by cycles of cell growth and division. The cell cycle diagram on the left shows that a cell division cycle consists of 4 stages:
G1 is the period after cell division, and before the start of DNA replication. Cells grow and monitor their environment to determine whether they should initiate another round of cell division.
S is the period of DNA synthesis, where cells replicate their chromosomes.
G2 is the period between the end of DNA replication and the start of cell division. Cells check to make sure DNA replication has successfully completed, and make any necessary repairs.
M is the actual period of cell division, consisting of prophase, metaphase, anaphase, telophase, and cytokinesis.
The correct answer is - Theory of the Ekman spiral
V. W. Ekman or Vagn Walfrid Ekman was a Swedish physical oceanographer. He is famous for his studies of the dynamics of ocean currents. Ekman developed a theory called as the “theory of the Ekman spiral”. This theory explains maintaining balance between frictional effects in the ocean and the Coriolis force. The force arises from moving objects in a rotating environment such as planetary rotation.
The appropriate answer is D. Alfalfa. Alfalfa is a legume and these plants play a key role in the nitrogen cycle. These plants house nitrogen fixing bacteria on their roots. The bacteria are housed in tiny round structures of leguminous plant roots. Once the nitrogen is fixed in the soil it can now be used by other plants to make food. These plants include beans peas and peanuts. <span />
