True or false
Calcium
Calcium
If I have 10 cookies and one person asks for one how many more do I have
11 I turn the guy into a cookie
Achoo
gesundheit
Pineapple
False
spell Stupid
Stoopiddulol
Can you eat a car
only if you try
Is the earth flat
No it is dinosaur shaped
Can you eat the sun
I depends on your shoe size
Waffle
Octopuses are among the strangest animals on Earth, and their circulatory system is a particularly good example of how evolution can produce a solution that seems almost backwards compared with the systems found in humans and many other animals.
An octopus has three hearts, blue blood, and a circulatory system that behaves differently depending on whether the animal is swimming or crawling. None of these features exist simply because octopuses are “weird.” Each is connected to the particular physical demands of living underwater, especially the problem of obtaining enough oxygen.
Oxygen is essential for producing energy.
Humans solve the oxygen problem by breathing air into lungs. Oxygen passes from the lungs into the blood, where it binds to hemoglobin. The heart then pumps the oxygen-rich blood throughout the body.
Water contains oxygen too, but extracting it is considerably more difficult than extracting oxygen from air. Fish and many other aquatic animals use gills, which provide a large surface area across which oxygen can move from water into the bloodstream.
Octopuses also use gills.
An octopus draws water into its body, moves that water across its gills, extracts oxygen, and then expels the water. The oxygen enters the bloodstream and needs to be transported throughout the animal.
This is where the three hearts become useful.
An octopus has two branchial hearts and one systemic heart.
The two branchial hearts are associated with the gills. Each one pumps blood through one of the gills.
Their job is essentially to push oxygen-poor blood toward the gills so that the blood can pick up oxygen.
After passing through the gills, oxygenated blood travels toward the systemic heart.
The systemic heart then pumps that oxygen-rich blood throughout the rest of the body.
So, in simplified form:
body → branchial hearts → gills → systemic heart → body
This arrangement is different from the familiar human system, where one heart performs the central pumping work for both the lungs and the rest of the body.
The octopus instead divides some of the pumping responsibilities between different hearts.
The answer has to do with blood pressure and resistance.
When blood passes through a respiratory organ, it encounters resistance. The gill is not simply an empty tube through which blood flows effortlessly. Blood must move through an intricate network of tiny vessels associated with the gill tissue.
The branchial hearts provide the pumping force needed to move blood through these structures.
Once the blood has been oxygenated, it reaches the systemic heart.
This creates a useful division of labor: the branchial hearts specialize in sending blood through the respiratory system, while the systemic heart specializes in distributing oxygenated blood to the body.
Evolution has repeatedly produced different arrangements for solving the same fundamental problem. Fish, mammals, insects, amphibians, reptiles, and cephalopods all transport gases and nutrients, but their circulatory systems are remarkably different.
How to get plant grow
water, soil and motercycle
How many points is this question worth
400
Bacon or ham
Bam
What is the answer
Violece
Is this real?
What you can directly experience is real as an experience.
Beyond that, there are layers:
So if you're asking for the one thing you can be most certain of: something is happening right now, and you are experiencing it.
Why did the chicken cross the road
To eat KFC