A control group of the experiment is the one in which no treatment or intervention is given. So, in your case, the pea plants in which was not subjected any of the fertilizers, will serve as a control group. This is a negative control. A positive control group is the one in which an established treatment is given, which definitely leads to the production of the desired character. So, in your case, a very good well-known fertilizer which has a positive control on the growth of the pea plant, would serve as a positive control.
<span> </span><span>Bean roots will have no nodules if there are no compatible Rhizobium bacteria in the soil. The nodule is a symbiotic relationship between the plant and the bacteria. Nitrogen fixing root nodules are pinkish in color. Green root nodules indicate actively reproducing bacteria that are not fixing nitrogen. The number of nodules depends on the amount of innoculant (Rhizobium) available in the soil. Look at the photos and make an estimate like x nodules per y linear inches of root. Hope this helps.
The edible part of the radish root functions as a food storage organ. The string parts of the radish root function as normal roots absorbing water and dissolved nutrients. Bean roots have no modifications for food storage. Radish roots don't have nodules. The radish root is a "tap root". The bean root is a "fiberous root"
Beans don't grown faster than radishes because of the root nodules. Bean seeds are large. Radish seeds are small. The energy stored in the bean cotyledons helps the seedling get a fast start. The radish gets a slower start from less stored energy.</span>
The order of flow of oxygen within the human body may be described simply. Oxygen first is inhaled through the nasal cavity and then passes through the trachea, through the bronchi and into the lungs. In the lungs, the oxygen is passed into the blood stream through the alveoli and then is carried to the heart. The heart pumps this oxygenated blood throughout the body, primarily to organs and muscle cells, where it is consumed in respiration and is converted to carbon dioxide and excreted.
The answer is A: a flagship species.
Hope this helps :)
