Answer:
A.The hole in the ozone layer
Explanation:
• Montreal protocol is an international treaty that was signed to control the use of substances that are resulting in the depletion of the ozone hole.
This treaty was signed in the year 1987 and became effective form 1989.
• Since the time that this treaty has come into force, there has been a significant improvement in the ozone hole that was observed over Antarctic as it's size has decreased.
• This improvement has been possible because the treaty helped to phase out chemicals such as chlorofluorocarbons, carbon tetrachloride, etc. that are responsible for ozone hole depletion.
False
http://www.h4hinitiative.com/hydration-science/hydration-lab/hydration-pregnancy-and-breastfeeding/c...
Answer:
C. Molecules such as cyclins are in high concentration in the cytoplasm of a dividing cell and will signal the fused cells nucleus to undergo mitosis
Explanation:
Various stages of the cell cycle are under tight regulation. Specific proteins such as cyclins and cyclin-dependent protein kinases determine if the cell would progress from one stage of the cell cycle to the next. When a cell is in the metaphase, the cyclins specific for mitosis are present in a higher amount in the cell. These cyclins bind to the specific CDKs and activate them.
The activated CDKs then phosphorylate proteins that make the cell to move through various stages of mitosis. Therefore, fusing a G1 cell with a cell in metaphase of mitosis would trigger mitosis in the G1 cell due to the presence of mitosis specific cyclins in the second cell.
Genes. Chromosomes carry genes that contain genetic information of the organism it is in.
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In the Northern Hemisphere, winter generally begins on December 21 or 22. This is the winter solstice, the day of the year with the shortest period of daylight. Summer begins on June 20 or 21, the summer solstice, which has the most daylight of any day in the year. Spring and fall, or autumn, begin on equinoxes, days that have equal amounts of daylight and darkness. The vernal, or spring, equinox falls on March 20 or 21, and the autumnal equinox is on September 22 or 23.
