# Make the internet a better place to learn

1

## What was the final event that caused England and France to declare war on Germany?

David Drayer
Featured an hour ago · World History

If you are talking about world war II it was the invasion of Poland by Germany.

#### Explanation:

England had appeased Germany's ambitions before the invasion of Poland. When Germany reoccupied the Rhineland in defiance of treaties signed after World War I France and England accepted the excuse that the Rhineland had always been part of Germany. When part of Cezkeslovika was invaded Germany's explanation that it was only to protect ethnic German's living there was "believed" . When Germany occupied Austria it was because the Austrians wanted the Germans to come in and rule them. This excuse was also allowed to stand.

However when Germany invaded Poland there was no excuse and England and France honored their commitments to Poland and declared war on Germany. This actually did not help Poland, as the Polish forces being attacked by Germany on three fronts and the Russians on a fourth front were over run and destroyed before any help could come from Poland's allies.

The invasion of Poland by Germany was successful and quick. The invasion however did cause England and France to declare war on the Axis Powers.

2

## How does the transfer of energy throughout an ecosystem begin?

Mila W.
Featured 4 hours ago · Biology

The sun, in almost all cases.

#### Explanation:

99.99% of living things on Earth get all of their energy from the sun. Plants start the food web, getting their energy directly from the sun through photosynthesis. Any animals that eat the plants take that energy, and animals that eat those animals get their energy thirdhand, and so on. Energy can travel this way from the sun to even the deep sea, where scavengers devour whatever dies and falls from the sunlit surface.

Interestingly, in the deepest parts of the oceans, energy can come from another source - the Earth's mantle. Hydrothermal vents, or "black smokers", are vents that spew superheated water heated by the magma below the crust. Various types of bacteria have evolved to survive on the nutrient-rich water, and these are in turn eaten by giant tube worms, yeti crabs, and clams. Those in turn are eaten by the deepest scavenger fish and a few species of octopi.

2

David Drayer
Featured 4 hours ago · Biology

1 A 2. C 3. A 4. A 5. B. 6. C

#### Explanation:

1. The geese are presently undergoing an exponential growth

2. There is a competition between different species, which the geese are winning. inter is between difference species.

3. The geese population will peak and then suffer a rapid decline.
There will be no room for further population increases. The geese will not have enough room for nesting, the food supply will not be sufficient to feed the increasing population.

4. 41 000/1000 = 41 it looks like there is a typo in the answer choices.

5. The birth rate is increasing while the death rate is going down.

6. It is most likely going to cause micro evolution. Some geese will have DNA adaptations that will allow some of the geese to exploit
new niches to succeed in intraspecies competition.

1

## What is the word for membrane proteins that have carbohydrates attached to them?

Michelle
Featured 4 hours ago · Biology

glycoprotein

#### Explanation:

A membrane protein that has a carbohydrate (sugar) attached is called a glycoprotein.

Membrane glycoproteins have various roles in cell communication, including:

• cell-to-cell recognition - glycoproteins can bind together if they find a glycoprotein that "matches" on another cell
• helping the immune system recognize foreign invaders
• acting as a receptor: viruses use glycoproteins embedded in the plasma membrane to bind to cells, and protein-based hormones bind to receptors in the cell membrane
• differentiating blood types: the different blood types (A, B, AB, and O) are due to certain glycoproteins being absent or present on the cell membrane

2

## How are nutrients absorbed and transported from the small intestine?

The nutrients are absorbed through the epithelium of villus into blood capillaries and lacteal. Then, they transported by the cardiovascular system and lymphatic system

#### Explanation:

The small intestine consist a large number of villi.

Villi under scanning electron microscope

Nutrients is divided into two groups, water-soluble and lipid-soluble. As the digested product from the stomach enter duodenum followed by ileum, the macromolecules is hydrolysed into small substances with the help of enzyme. The water-soluble substances then pass through the epithelium of villus to enter the blood capillaries while the lipid-soluble substances enter the lacteal. The water-soluble substances will then be transported to whole body by cardiovascular system while lipid-soluble substances will then transported by lymph and end up to be in the cardiovascular system.

Picture of a villus

1

## What are the two forms of genetic drift and examples?

Michelle
Featured 3 hours ago · Biology

The two forms of genetic drift are the bottleneck effect and the founder effect.

#### Explanation:

Genetic drift is an unpredictable change in the gene pool, and it usually limits diversity because some alleles become either eliminated or expressed too much.

Two forms of genetic drift are the founder effect and the bottleneck effect.

1. Founder effect

When a small group of individuals breaks away from a larger population and creates its own population in a separate location, rare alleles could be overrepresated in this newly "founded" population. If this new population is isolated and interbreeds, then the resulting population could have a high frequency of certain traits.

Example: The Afrikaner (Dutch) population that settled in South Africa had an abnormally high count of Huntington's Disease, because the first Dutch settlers had a high frequency of the gene (compared to the original Dutch population).

2. Bottleneck effect

The bottleneck effect occurs when a random event, such as a natural disaster, unselectively reduces the size of a population. The resulting population is much less genetically diverse than the original population. Some alleles may become entirely eliminated and some may become overrepresented .

Example: After the northern elephant seal almost went extinct as a result of extensive hunting, the seal was placed under government protection. Since then, the population has grown, but all the descendants have little genetic variation since so few elephant seals remained.

2

## Typically, how many days does an egg live after its released from the ovary?

EET-AP
Featured yesterday · Anatomy & Physiology

An egg can usually live for 12 to 24 hours (or one day) after it is released from the ovary, after which the egg will disintegrate and trigger the next menstrual cycle

#### Explanation:

Meanwhile, sperm can survive inside the female body for up to five days, so pregnancy can still occur if the activity has taken place before the egg has been released.

Pregnancy timing is a complicated procedure which may require professional help or body fluid monitoring if the goal is to become pregnant.

If the goal is not to become pregnant, then reliable birth control is required every time, and trust no one but yourself to keep you safe.

http://teenhealthsource.com/pregnancy/pregnancy-happen/

1

## Can you very shortly summarize each section of Farenheit 451 by Ray Bradbury?

David Drayer
Featured 10 hours ago · English Grammar

The Hearth and the Salamander : Waking up to the Emptiness of the world where no one can be offended or made to think.
The Sieve and the Sand : Montage realizes the immensity of trying to change the world, or even Mildred.
Burning Bright; The destruction of Montage's world personal and city.

#### Explanation:

The Hearth and the Salamander Montage is told how the firehouse society is built to avoid offending any minority. No one is to be allowed to be superior to anyone else. This results in an emptiness of human spirit and relationships.

The Sieve and the Sand: Montage tried to change his wife to rebuild a relationship with her, but she was too tied to her "family". He tried to wake Mildred's friends but only makes them angry and cry. His plans with the professor seem doomed to have much affect.

Burning Bright. Montage's house is burned down along with his relationship with Mildred. Beatty is burn along one hound and his career. Then the entire city is burned in an atomic war. This opens the possibility of building a new world.

1

## How do you divide (6x^2+41x+31) -: (x+6)?

Tony B
Featured 8 hours ago · Precalculus

$6 x + 5 + \frac{1}{x + 6}$

#### Explanation:

color(white)(?)

$\text{ } 6 {x}^{2} + 41 x + 31$
color(white)(?)color(magenta)(+6x)(x+6)->ul(6x^2+36larr" Subtract"
$\text{ } 0 + 5 x + 31$
color(white)(.?)color(magenta)(+5)(x+6)->" "ul(5x+30)larr" Subtract"
" "color(magenta)(0+1 larr" Remainder")

$\textcolor{m a \ge n t a}{6 x + 5 + \frac{1}{x + 6}}$

3

## Why does adding "AgNO"_(3("aq")) to "I"_(2("s")) rightleftharpoons "I"_(2("aq")) cause the aqueous iodine to precipitate into a solid?

Michael
Featured 3 hours ago · Chemistry

Here's my take on this:

#### Explanation:

Iodine reacts with water and the following equilibrium is established:

$\textsf{{I}_{2 \left(s\right)} + {H}_{2} {O}_{\left(l\right)} r i g h t \le f t h a r p \infty n s O {I}_{\left(a q\right)}^{-} + 2 {H}_{\left(a q\right)}^{+} + {I}_{\left(a q\right)}^{-}}$

The position of equilibrium lies well to the left.

Adding aqueous silver nitrate would cause a yellow precipitate of silver iodide to form:

$\textsf{A {g}_{\left(a q\right)}^{+} + {I}_{\left(a q\right)}^{-} \rightarrow A g {I}_{\left(s\right)}}$

On this basis, according to Le Chatelier, you would expect the position of equilibrium to be shifted to the right, causing more solid iodine to dissolve.

The question states that the opposite takes place.

I think this hinges on how you interpret exactly what you mean by $\textsf{{I}_{2 \left(a q\right)}}$. This is routinely described as "aqueous iodine" or "iodine solution" and is used in volumetric analysis and as a qualitative test for starch.

In reality, because of the low solubility of iodine in water, it is actually a solution of iodine in potassium iodide solution.

The equilibrium is established:

$\textsf{{I}_{2 \left(s\right)} + {I}_{\left(a q\right)}^{-} r i g h t \le f t h a r p \infty n s {I}_{3 \left(a q\right)}^{-}}$

The charged $\textsf{{I}_{3}^{-}}$ ion being more soluble such that sf(K=~400).

If the question actually means that sf(I_(2(aq)) is really a solution of iodine in KI solution then adding $\textsf{A {g}_{\left(a q\right)}^{+}}$ would form a precipitate of AgI, thus removing $\textsf{{I}_{\left(a q\right)}^{-}}$ from the equilibrium. This would cause the position of equilibrium to shift to the left, producing more solid iodine.