The valves are responsible for preventing blood from flowing in the wrong direction, they are present in the veins, and the arteries don't need them because the aorta (biggest artery) pumps or in other words pushes it with such a force that no other force can change its direction, in the veins there is no structure present for pumping them as a result we have got valves so that they go in one direction...... the meaning of the word valve is to allow in one direction
In the Northern Hemisphere, winter generally begins on December 21 or 22. This is the winter solstice, the day of the year with the shortest period of daylight. Summer begins on June 20 or 21, the summer solstice, which has the most daylight of any day in the year. Spring and fall, or autumn, begin on equinoxes, days that have equal amounts of daylight and darkness. The vernal, or spring, equinox falls on March 20 or 21, and the autumnal equinox is on September 22 or 23.
<u>Answer:</u>
<em>The diet that helps in preventing cancer is “a diet high in fiber and low in saturated fats.</em>
<u>Explanation:</u>
Though cancer cannot be fully prevented or cured by the <em>healthy diet </em>but the risk can be lowered. By having the diet that is rich in fiber like, broccoli, beans etc. helps in preventing the risk of esophageal cancer.
The intake of oranges, berries, peas etc. helps in reducing the stomach and esophageal cancer as they are low in<em> fats and high in fiber contents.</em>
Answer:
By using too much Fossil fuels like coal and oil, gas.
<u>Answer</u>: Hybridization.
Hybridization is the process through which two species can mate with each other and produce fertile offspring thus creating a new species.
This is not happening with the two palm species on the island. This may be due to prezygotic barriers that prevent these two species from mating and producing a zygote (fertilized egg cell). In essence these barriers prevent any gene flow between the two species.
