Answer:
By providing an example using one organ for each of the four levels of complexity, we have the following:First level organ: Skin; this is because it takes up a few cells. Second level organ: Windpipes; this is because they have more complex shapes with multiple cells. Third level organ: Stomach; this is because the stomach has to act on demand instead of a flow. Fourth level organ; Heart. The reason it is difficult to make level four organs in a lab is that it has a complicated architecture with several cells, blood vessels and tiny capillaries included. So far, scientists are yet to fully develop solutions for the level four organs and hence, difficult to create in a lab.
Explanation:
Answer:
Teenager's circadian rhythms – the cycle of sleep and wakefulness – typically begin two hours after adults. Neuroscientists say they are biologically predisposed to go to sleep around midnight and not feel fully awake and engaged until between 9am and 10am
Explanation:
D is correct. The cylinder's marking are closer together and are more precise.
<span>Doctors do not administer vaccinations to people who are too sick because (option D.) the white blood cells of sick people may not be able to efficiently handle the weakened or dead form of the pathogen. The inmunization is obtained when the white blood cells attack the weakened form of the pathogen, so if the white blood cells are working against other ill then they may not be able to effeciently attack the injected pathogen. </span>
The United States are entirely located in the Northern Hemisphere. It is bordering Canada on the north, and the air masses that form over it have big influence on the climate of the United States. Most of the United States falls under the influence of the air masses coming from the north, with only the southern parts of the east and west coastlines not being heavily affected. The air masses that form over Canada are cold continental air masses. They move towards south, thus toward the United States in November, quickly pushing the warmer air masses, and replacing them, bringing in cold weather conditions, which last until March.