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9

## What organ system does the kidney belong to? What organ system does the liver belong to?

Saikat R.
Featured 44 minutes ago · Anatomy & Physiology

Kidneys belong to Excretory system.
Liver belongs to Alimentary system.

#### Explanation:

Kidneys are part of the excretory system (urinary system). This system is associated with excretion of metabolic waste products and formation and excretion of urine. Other organs of the system are ureters, urinary bladder and urethra.

The diagram of excretory system :

Liver is a part of the alimentary system (other name is digestive system). This system has two main parts : Digestive tract and digestive glands. From mouth to anus all organs (mouth, esophagus, stomach, small intestine, large intestine, rectum and anus) form a tract, which is called digestive tract.
Salivary glands, Liver and pancreas are part of digestive glands.

As the name suggests the digestive system is associated with digestion, absorption and metabolism of nutrients. Liver forms bile, which is essential for fat digestion and absorption. And liver is the organ of metabolism. So it belongs to alimentary (digestive) system.

A Diagram of alimentary (digestive) system :

Sometimes Liver, gall bladder and bile ducts (the organs related to bile production and secretion) are included into a system called the Hepatobiliary system.

3

## What is the density of NH3 at 800 torr and 25 degrees C?

anor277
Featured 2 days ago · Chemistry

I do not know why they ask these questions with whack units...........

#### Explanation:

If I had come across a question which quoted a pressure of $800 \cdot m m \cdot H g$ in my A2 syllabus, I would raise merry hell. We know that $1 \cdot a t m$ will support a column of mercury that is $760 \cdot m m$ high. A mercury column is thus a good visual gauge for pressures at $1 \cdot a t m$, or pressures below $1 \cdot a t m$. I am a bit peeved by this issue, because last month the head of school (the creature) vetoed my use of mercury columns in the science lab, while in the Geography lab, they have a pair of antique mercury barometers that have probably never been used.

You raise or try to raise the mercury column over $760 \cdot m m$ you will probably get mercury all over the laboratory or the classroom. You can use (preferably for chemists) $\text{atmospheres}$, or $\text{kilopascals}$, or even $\text{pounds per square inch}$. You do not use $m m \cdot H g$ for pressure OVER atmospheric.

Anyway to your problem, the pressure is.....

$\frac{800 \cdot m m \cdot H g}{760 \cdot m m \cdot H g \cdot a t {m}^{-} 1} = 1.053 \cdot a t m$.

We assume a volume of $1 \cdot L$, and then we solve the Ideal Gas equation.............

$P V = n R T$, and thus $\frac{P}{R T} = \frac{n}{V} = \frac{\text{mass"/"molar mass}}{V}$, and so..

(Pxx"molar mass")/(RT)="mass"/V=rho_"density". $\text{Whew...........}$

And thus ${\rho}_{\text{ammonia}} = \frac{1.053 \cdot a t m \times 17.03 \cdot g \cdot m o {l}^{-} 1}{0.0821 \cdot \frac{L \cdot a t m}{K \cdot m o l} \times 298 \cdot K}$

$= 0.7 \cdot g \cdot {L}^{-} 1$

2

## If A+B+C =180^@, prove that cot^2 A + cot^2 B +cot^2 C >= 1 ?

dk_ch
Featured 15 hours ago · Trigonometry

$A + B + C = {180}^{\circ}$

$\implies \cot \left(A + B\right) = \cot \left({180}^{\circ} - C\right)$

$\implies \frac{\cot A \cot B - 1}{\cot B + \cot A} = - \cot C$

$\implies \left(\cot A \cot B - 1\right) = - \left(\cot B + \cot A\right) \cdot \cot C$

=>(cotAcotB+cotBcotC+cotCcotA=1

Now

${\cot}^{2} A + {\cot}^{2} B + {\cot}^{2} C - 1$

$= {\cot}^{2} A + {\cot}^{2} B + {\cot}^{2} C - \left(\cot A \cot B + \cot B \cot C + \cot C \cot A\right)$

$= \frac{1}{2} \left(2 {\cot}^{2} A + 2 {\cot}^{2} B + 2 {\cot}^{2} C - 2 \cot A \cot B - 2 \cot B \cot C - 2 \cot C \cot A\right)$

$= \frac{1}{2} \left[{\left(\cot A - \cot B\right)}^{2} + {\left(\cot B - \cot C\right)}^{2} + {\left(\cot C - \cot A\right)}^{2}\right]$
This being sum of three squared quantities each of which is difference of two quantities. So this sum is $\ge 0$

Hence

${\cot}^{2} A + {\cot}^{2} B + {\cot}^{2} C - 1 \ge 0$

$\implies {\cot}^{2} A + {\cot}^{2} B + {\cot}^{2} C \ge 1$

1

## Are platelets, proteins, and vitamin K all required for homeostasis?

Samin Yasar
Featured 49 minutes ago · Anatomy & Physiology

Yes

#### Explanation:

I think you meant hemostasis not homeostasis. The former is the physiological process of bleeding arrest while the latter simply means a state of nearly constant condition that our body maintains.

Now assuming we are talking about stopping a bleeding , let me first review some basic principles. Remember that whenever there is a damage to our vessel wall, our body responds with three mechanisms :

1. Vasoconstriction to limit the blood flow to that region

2. A primary platelet plug formation to stop bleeding from that damaged area (primary hemostasis). But the plug is weak

3. Formation of a meshwork of fiber like substance (fibrin) on top of the platelet plug to stabilize the weak plug

Now with these concepts in my mind let us figure out the answer to your question.

Firstly, the roles of platelet is obvious because it forms the platelet plug (it actually takes part in all steps of hemostasis)

By proteins I assume you meant the clotting factors. The fibrin, I mentioned before, remains in blood as globular protein fibrinogen. In order to form polymerised fibrin from it, a series of reactions take place, reffered to as the Coagulation Cascade. Many clotting factor proteins participate in the cascade, acting as catalysts.

Vitamin K is necessary for the formation of some clotting factors (specifically factor 2, 7, 9 and 10) in liver.

So the whole process of stoppage of bleeding (hemostasis) requires all three of them.

2

## What is the difference between quasars, pulsars and neutron stars?

1s2s2p
Featured 2 days ago · Astronomy

See below.

#### Explanation:

A quasar is a form of galactic nuclei found at very large astronomical distances away from Earth (one of the closest is 3C 273, which is around 749Mpc away from Earth), because of this, they are theorized to have played a part in the earlier universe. They are several thousand times more luminous than the Milky Way, and are a supermassive black hole (SMBH) surrounded by a large accretion disk which orbits the SMBH. When matter from the accretion disk is 'absorbed' , energy is released as EM radiation, which are the two two glowing rays.

Neutron stars are what remains of the core of a supernova after it undergoes extreme compression from gravitational collapse once the outer layers have been exploded from the star. The compression squashes the core to extremely high densities, more than that of a white dwarf. They get their name as they are theorised to be completely made of neutrons.

A pulsar is a type of neutron star, which rotates with incredibly fast speeds, taking several milliseconds to a few seconds to complete one full revolution. They are highly magnetised and emit beams of EM radiation at opposite ends. They get their name as their light appears to pulsate, because they can only be visible if a beam points towards Earth. They are formed in the exact same way as a neutron star, except they keep some of their angular momentum, but as the radius is much smaller than the star, its rotational speed is increased. The pulsar has two axes, a rotational axis and a magnetic axis. The magnetic axis is where the beams are emitted from, while the pulsar rotates around the rotational axis.

2

## How does earth affect the solar system?

Oscar L.
Featured 2 days ago · Astronomy

Out Earth is only a small planet, but anything we now call a "planet" ends up having a profound effect on the Solar System. See the explanation below.

#### Explanation:

Three words: Clearing the neighborhood.

Back in 2006 this was the most controversial phrase in all of science, as it led to Pluto being rendered "not a planet". But the implications of clearing the neighborhood are literally seen across the orbit of the planet, an effect extending far beyond the immediate region around the planet itself.

Clearing the neighborhood means the region around the entire orbit of a planet is cleared of smaller bodies that could collide with the planet; what smaller bodies remain are either controlled and trapped by the combined action of the planet and the Sun, or trapped directly as moons.

In the case of the Earth, several asteroids are known where the asteroid is held as a companion of Earth in orbit, but never in position to collide with us. The Earth acting together with the Sun has them in control. One such asteroid is 3753 Cruithne, see https://en.wikipedia.org/wiki/3753_Cruithne.

There are also Trojan-type asteroids that orbit around the Lagrange points of the planet-Sun system, points selected by the combined gravity if the planet and Sun. Earth has 2010 TK7, Jupiter has lots of them, and most planets in our Solar System are known to have at least one. See https://en.wikipedia.org/wiki/Trojan_(astronomy).

And of course, There are moons. Earth has one which is, of course, what we call just "the Moon.

Apart from these controlled objects, we see very few things hanging around Earth's orbit because of Earth clearing the neighborhood. (Most of the "potentially hazardous asteroids that are found, get "demoted when we learn more about their orbits.) So it is with Mercury, Venus, and all other planets. They leave smaller, otherwise "uncontrolled" objects confined to planet-free zones like the asteroid and Kuipet belts.

Earth is truly among the "elite" bodies under the Sun, being one of only eight "planets capable of doing this over a range of billions of kilometers. Astronomers had good reason to distinguish beighborhood-clearing bodies from other round worlds when they defined "planets" in 2006.

1

## What is the gcf of 45 and 75?

sjc
Featured yesterday · Prealgebra

$g c f \left(15 , 45\right) = 15$

#### Explanation:

Another way is to list the factors and then pick out the common ones.

factors of $15 : \left\{\textcolor{red}{1 , 3 , 5 , 15} ,\right\}$

factors of $45 : \left\{\textcolor{red}{1 , 3 , 5} , 9 , \textcolor{red}{15} , 45\right\}$

common factors $\left\{1 , 3 , 5 , 15\right\}$

$g c f \left(15 , 45\right) = 15$

1

## What was the turning point in the war on the western front? When? Where?

Charlie P.
Featured 22 hours ago · World History

I wonder what war you are talking about, and whether it is WW1 or WW2.
WW1 mainly began to turn around in 1918.
WW2 mainly began to turn around on June 6, 1944 after the D-Day landings in Normandy.

#### Explanation:

The war on the western front in WW1 was a battle of attrition, with the constant bombarding of either side and waste of life as hundreds of men were sent 'over the top' into no man's land.

In 1916, the British produced the first Tanks, and used them at the Battle of the Somme, which was designed to be the beginning of the finishing blows against the Germans, however the Germans had dug in and were able to withstand the week long heavy bombardment and the mines set off. When the bombardment stopped, they were able to get back in time to their machine guns and mow down the lines of allied troops in no man's land.
This made the Somme a tragedy, but the new tanks were shown to be great assets in trench warfare, and could break through the deadlock the two sides had created.

The turning point of the first world war happened mainly after the German Spring Offensive in 1918, which was incredibly successful at first, but the supply lines got stretched so far, the troops had to retreat, surrender or threaten being destroyed by the allied armies. After that, the Germans continued the retreat back into Germany, where on the 11 of November in 1918, the armistice was signed and WW1 ended.

WW2 on the western front began to turn after the invasion of Normandy, France, in 1944, where a seaborne attack onto the beaches of Normandy took place.
Special tanks and weapons were formed to get on to the beaches, clear them of defenses and their defenders.
These tanks included the Duplex Drive Sherman- literally a swimming tank, the Churchill crocodile- a flame thrower tank, the Sherman/Churchill minesweepers and many more, I'd recommend reading into the topic.

There was also nightly bombing raids on Normandy before the invasion took place, to soften up some of the defenses, and the night of the invasion, Allied gliders and parachutists were sent in to capture and hold key strategic points such as bridges until the troops on the Normandy beaches could relieve them.

This invasion was a key turning point against Germany in Western Europe in WW2, and could be believe to have helped secure much of Europe from the Soviet Union, whom were on the offensive at this point in the war, most likely would have kept going until they reached the English Channel, which would have led us to see a much more different Europe than the one we have today.

Hope this answers your question, and educates you on the other War in Western Europe.

1

## What is an example of a vertical motion with a positive velocity and a negative acceleration?

Sarah Sayid
Featured 4 hours ago · Physics

Observe when an object moves in the positive direction with a changing velocity. An object which moves in the positive direction has a positive velocity. If the object is slowing down then its acceleration vector is directed in the opposite direction as its motion (in this case, a negative acceleration).

1

## How do you solve 5x-7>=13?

Bobert
Featured 3 hours ago · Algebra

x≥4

#### Explanation:

To solve this, use some basic algebra to isolate the unknown, x.

First, add $7$ to both sides.
5x-7+7≥13+7

=> 5x≥20

Next, divide both sides by $5$.
(5x)/5≥20/5

=>x≥4

The solution is =>x≥4.