One fourth means (one half) of (one half) .
So the 18 months must be two half-lifes.
The half-life of this particular isotope is 9 months.
<span>Great minds combined with technological advancements have a lead to creations and achievements that would have been impossible. Whatever great scientist of the past has achieved have already been surpassed or improved through modern and innovative ideas and processes. An excellent example of which is the direct manipulation of an organism’s DNA, also known as genetic engineering or genetic modification (GM). Coming from the terms genes and modify, the entire process is something out of a science fiction movie. Well, it used to be that way until the practice was perfected and used in actual applications. Genetic engineering made it possible to add new DNA or alter bad ones.</span>
Answer:
Explanation:
Green crabs have chemoreceptors located on an <em>antenna</em>.
These are long segmented appendages near the crab´s eyes that have both chemoreceptors and allow them to feel the surroundings.
Crabs also have antennules, like short appendages close to the antennas that allow them to <em>sense</em> their environment. A crab can "taste" using hairs on their mouthparts, pincers and even its feet.
So they can detect the salinity of the water by "taste" using the antennules. If these antennules are bathed with nonsalty water, the information the crab´s brain receives is to increase the salinity of its body by the system explained above, increasing its rate of urine production.
I hope it helps!
