Answer:
Helium neon and Argon are called inert gases are noble gas because they have complete its duplet as well as Octate. and no other element like Helium neon and Argon complete its octate and duplete. in the 18th period all element are inert. Which gas does not exist in air?
Explanation:
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Answer:
D. Thermal expansion
Explanation:
MECHANICAL WEATHERING
can be defined as the gradual disintegration of rock into smaller particles which later turn into soil. when mechanical weathering occurs, it doesn't change the chemical composition of the rock. mechanical weathering are caused by abrasion by ice water, thermal expansion, root of trees growing on the rock.
THERMAL EXPANSION
This is a mechanical process of weathering. during the day when there is high temperature and hits the rock surface, the rock absorbs heat expands . at night when the temperature drops the rock contrast. Repeated action of expansion and contraction results in gradual breakdown of rock to form soil.
Chinese hamster ovary cell production of recombinant tissue‐type plasminogen activator (t‐PA) was increased by amplification of cotransfected dihydrofolate reeducates cDNA using stepwise adaptation to increasing methotrexate (MTX) concentrations. The highest producing clones were isolated at 5 μM MTX and yielded 26,000 U/106 cells/day t‐PA (43 μg/106 cells/day). Above 25 μM MTX, cell specific t‐PA production rates became increasingly variable and the cDNA copynumbers decreased. No apparent correlation between the cell specific t‐PA production rate and the growth rate was observed upon sub cloning of the amplified cells. When MTX selection was removed, the t‐PA production rate decreased up to tenfold within 40 days; this was accompanied by an up to 60% drop in cDNA copynumber. Subclones isolated after 108 days of culture in the absence of MTX were, on average, sixfold more stable than their parental cells. In culture without MTX, the maximum stable t‐PA production rate obtained (over 250 days) was 7000 ± 750 U/106cells/day (∼12 μg/106 cells/day), approximately threefold lower than the maximum unstable levels of production reached under selective pressure. Taken together, these results define a wide range of the highest t‐PA expression rates obtained under MTX selection, for which stable expression without selection has not been reported
Answer:
Interphase: growth and development.
Prophase: nucleus begins to disappear and chromosomes are now visible.
Metaphase: the chromosomes align in homologous (the same) pairs in the middle.
Anaphase: The chromosomes begin to move to opposite ends of the cell.
Telophase: The animal cell punches in (creating cleavage) and the plant cell creates a cell plate to help divide the cell.
Cytokines: The cells are completely apart.
