Hello there.
<span>Regulation of the cell cycle is dependent upon cyclins and cyclin-dependent kinases. The key(s) that allows a cell to progress beyond the restriction point is (are)
</span><span>c. cyclin A and Cdk2.
</span>
False
<span>Marine ecosystems like lakes and oceans have aphotic zones. Aphotic zones refer to the zones in the water where there is little or no sunlight. It is found in bodies of water were depths only receive less than 1% of sunlight penetrations. Bioluminescence is essentially the only light found in this zone and most food comes from dead organisms that sink at the bottom of lakes or oceans. </span>
The fluid in which organelles of the cell reside. This water can be used to assist in chemical reactions within the cell.
None of the provided options are reasonable. <span>comparing nutrient concentrations between the photic zone and the benthic zone can not tell you whether differences in concentrations between the photic and benthic zone are due to uptake by phytoplankton or because nutrients are sinking to the sea bottom and ocean stratification is preventing mixing. The approach of c</span><span>ontrasting nutrient uptake by autotrophs at different locations under different temperatures would not provide useful information on limiting nutrients. but rather uptake rates at different temperatures. It is likely that e</span>xperimentally enriching some areas of the ocean and compare their productivity to that of untreated areas can provide an indication of limiting nutrients, but this is not advisable, as it would have to be done on a large scale, and one cannot be sure of the ecological consequences. Also, because it would not be a controlled experiment, other factors could create 'noise' in the data. The last option, <span>observe antarctic ocean productivity from year to year to see if it changes, also does not help, as there is no correlation between nutrient concentrations using this approach. The best approaches would be either the last approach, but with the additional monitoring of nutrient concentrations, or under a controlled laboratory experiment.</span>
The rungs are composed of hydrogen bonded paired Nitrogenous Bases. These pairings are Adenine to Thymine and Guanine to Cytosine.
