and closing
.
The heart has 4 valves. They are what makes the lub-dub lub-dub sounds that can be heard from the chest.
The mitral valve is located between the left atrium and the left ventricle. It closes the left atrium to collect oxygenated blood from the lungs and opens to pass it on to the left ventricle.
The tricuspid valve is located between the right atrium and the right ventricle. It closes the right atrium to hold unoxygenated blood and opens to pass it on to the right ventricle ensuring a one way flow.
The aortic valve is located between the aorta and the left ventricle. It closes the left ventricle and opens to the aorta to pass on the oxygen-rich blood to the body.
The pulmonary valve is located between the pulmonary artery and the right ventricle. It closes off the right ventricle and opens to pass on unoxygenated blood to the lungs.
I THINK C BECAUSE IF IT IS A GLASS BOX HOW DID A CACTUS GET IN AND NOTHING CAN GET IN OR OUT OF THE BOX SO THERE IS NO CACTUS IN THE BOX
The most important characteristics that are exhibited by metals are-
1- Metals are ductile
2-Most metals are conductive in nature.
3-Most metals are malleable.
4- Metals have strong inter molecular force of attraction between the.
5-Metals have luster.
6-Metals are sonorous.
Here we are given Tungsten filament.
Tungsten is a metal.So it must be conductive and as well as ductile in nature.
The electric filament that we are using in our electric bulb glows due to the heating effect of current.Hence the chosen substances for glowing electric bulb must have high melting point.
The melting point of tungsten is 1650 degree celsius which is very high.That's why it is used in electric bulb.
Hence the correct answer to the question is the third one i.e Tungsten is ductile,has a high melting point, and is electrically conductive.
Answer:
option C
Explanation:
given,
force act on west = 20 lb
force act at 45° east of north = 80 lb
magnitude of force = ?
∑ F y = 80 cos 45⁰
F y = 56.57 lb
magnitude of forces in x- direction
∑ F x = -20 + 80 sin 45⁰
= 36.57 lb
net force
F = 
F = 
F = 67.36 lb≅ 67 lb
hence, the correct answer is option C
Explanation:
"The burning of fossil fuels , oil and natural and power from nuclear power provide about 87% of the energy used in the world.
Coal, natural gas, petroleum and nuclear power are the major energy providers to the whole world. Till date we are heavily depend on them. They provide for about 87% of the total energy used in the world.
