I think it would be the first one
Answer:
A. Tapeworm in an intestinal tract.
Explanation:
This symbiotic relationship is parasitic because the tapeworm causes harm to the host. Tapeworms feed off the nutrients the host consumes, thus making the host sick.
Not parasitic:
Bees transport pollen from flowers back to the nest to feed the young bees, but pollinate female flowers as well which keeps the flower population alive.
Pilot fish swim under sharks to keep other prey from eating them, and the shark do not eat eat the pilot fish.
Birds eating the insect of the back of a hippopotamus keep the hippo clean and parasite-free as well as feeding the birds.
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:
we do it to select the best seeds
the seeds floating on the top are bad seeds which are empty inside
the seeds that are on the bottom are good seeds they are heavy
A landform is simply any natural geographic feature that can be found on the earth’s surface, such as valleys, hills, mountains and plateaux. Landforms are all not the same. Some may be very high above sea level and other parts may be deep below sea level. Some of them are made of very hard material and other parts may be made of very soft material. Some landforms are covered by vegetation whiles some are void of any plant at all. Some are very large and others are small. Most important of all, landforms are constantly changing because the factors that form them are in action everyday! - landforms
A relief map is a 2 or 3 dimensional map that shows varying elevations. On 2 dimensional versions shading is done using different colors are used to show varying degrees of elevation for things like mountain ranges. The 3 dimensional maps are the most impressive. Combined with the color a variety of different materials –plastic, rubber etc. –are used to display different features like valleys, mountains, rivers. The result is a map on which you can actually see and touch the top of Everest and the floor of Death Valley. - relief map