If a red blood cell is placed in a hypertonic solution, the cell would shrink.
Hypertonic solution means that the solution has a lower water potential than the other side (which is the cell's cytoplasm in this case), and by that, water molecules would have a tendency to flow from a region of higher water potential to a region of lower water potential. This movement of water molecules is called osmosis. But note that a semi-permeable membrane (a membrane which can decide what substances can go in and out, the cell membrane is an example) has to be present in osmosis, or else the movement may be regarded as diffusion.
As the water molecules flowed away from the red blood cell cytoplasm, the cell loss so much water that the membrane has nothing much to hold and thus the cell shrinks.
Answer:
Option 2, Arousal
Explanation:
Reticular activating system (RAS) or the ascending arousal system consists of nuclei and tracts and is involved in the regulation of wakefulness, sleep aspects and arousal.
RAS is located in the mesopons and interacts with the basal forebrainand thalamocortical systems. It activates the cerebral cortex and thereby maintain the consiusness. The neurons located at the pontomesencephalic junctionparticipates in this activity of arousal.
Hence, option 2 is correct
Answer:
Since the origin of humans on this planet, they have been trying their best to make their lives easier on this planet. In doing so, human activities have some how heavily damaged the Earth. Many day to day activities of humans are dangerous for the Earth.
Some of the consequences of human activities on the Earth's fresh water are :
Extinction of many aquatic species:
The water consumed by humans comes from the fresh water oceans. As the population of humans is increasing enormously, the water from the oceans is being consumed at dangerous levels. This has caused many species of aquatic animals to become extinct or to be at a verge of extinction as they do not have a habitat to survive or reproduce.
Pollution:
Many heavy industries, house sewage, farmers dispose waste into the fresh water. Hence, killing aquatic animals and polluting the fresh water ecosystems.
