Answer:
1.75 billion years
Explanation:
Scientists have concluded that Earth could potentially continue to host life for at LEAST another 1.75 billion years. As long as there's no natural disasters or nuclear wars, we should be good. (Right?)
But, eventually, over time Earth will become uninhabitable. :o
Answer:
1. Aortic semilunar valve
2. Tricuspid valve
3. Mitral valve
4. Pulmonary semilunar valve
5. Mitral Valve
6. Tricuspid valve
Explanation:
The four heart valves of our heart have two main functions. They open to allow blood to pass through them, and close to prevent blood from going back (backflow).
Semilunar valves:
There are two semilunar valves and they have 3 cusps. They open up to areas outside the heart. Their main function is to prevent backflow towards the heart.
a. Aortic semilunar valve is located in between the Aorta and the left ventricle. It opens up to the Aorta where oxygen-rich blood leaves the heart and go towards the other parts of the body. It prevents backflow to the left ventricle.
b. Pulmonary semilunar valve is located in between the right ventricle and the pulmonary artery. It opens up to the pulmonary artery which carries unoxygenated blood towards the lungs. It prevents backflow to the right atrium.
Atrioventricular valves:
They are named as such because they are found in between the atria and the ventricles.
a. Tricuspid valve has three cusps and it is found on the right side of the heart. It is located in between the right atrium and the right ventricle. It prevents backflow to the right atrium.
b. Mitral valve has 2 cusps and that is why it is also known as the bicusip valve. It is located in between the left atrium and the left ventricle. It prevents backflow to the left atrium.
Plant cells have cell walls but animal cells don't. That's one of the things that make their structures different.
It refers to Calorific flow
