Answer:
they give the lungs a really big surface area. they have moist, thin walls (just one cell thick) they have a lot of tiny blood vessels called capillaries.
The walls of the alveoli are only one cell thick. This makes the exchange surface very thin - shortening the diffusion distance across which gases have to move. Each alveolus is surrounded by blood capillaries which ensure a good blood supply.Adaptations of the alveoli:
Thin walls - alveolar walls are one cell thick providing gases with a short diffusion distance. Moist walls - gases dissolve in the moisture helping them to pass across the gas exchange surface. Permeable walls - allow gases to pass through.
Explanation:
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The correct answer is Birth.
The two elements that raise population size are natality—the number of people who are added to a population over time as a result of reproduction—and immigration—the movement of people into a location. Most births are to folks who are young adults or older. Even at replacement fertility levels (when each woman has approximately an average of two children), there will be more births than deaths if the proportion of young adults to older adults is higher where mortality is highest. Immigration and birth rates lead to population growth. The population shrinks as a result of death rates and emigration. A population that has a negative growth rate is one in which there are more deaths and emigrants than births.
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Answer:
b. all three pathogens are obligate anaerobes.
Explanation:
Tetanus is caused by an <u>exotoxin</u> produced by the bacterium <em>Clostridium tetani</em>, which is normally f<u>ound in the soil</u>, although it may be present in the intestines of mammals. It is an <u>anoxic and spore-forming bacteria</u>. It enters the body through wounds or deep punctures, finding in the wound the anoxic conditions to germinate its spores, producing its potent toxin.
Anthrax is caused by the bacterium <em>Bacillus anthracis</em>, which is a stationary and <u>endospore-forming </u>bacteria that is resistant to high temperatures and chemicals. It is a <u>strictly aerobic</u> bacterium and can be <u>found naturally in the soil</u>. Both animals and humans can breathe or ingest spores of this bacterium by consuming meat or contaminated water. When spores get into the body, their turn into active cells and <u>produce exotoxins</u>
Botulism is caused by the pathogen <em>Clostridium botulinum</em>, a s<u>trict anaerobic</u> bacillus, producing <u>endospores and 8 different types of toxins</u>. Being a <u>soil-borne bacterium</u>, it usually appears in the food of animal and vegetable origin.
The correct answer is A. R and S
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Answer:
C erosion
Explanation:
its taking away part of the beach, and it happens slowly over time