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4 years ago

What is gaseous exchange

1 answer:

7 0

Gas exchange is the delivery of oxygen from the lungs to the bloodstream, and the elimination of carbon dioxide from the bloodstream to the lungs. It occurs from the lungs between the alveoli and a network and a bunch of tiny blood vessels called capillaries, which is located in the walls of the alveoli.

~Sorry if I typed some stuff wrong, I'm eating a popsicle while typing this~

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Which statement best describes peristalsis?

Hatshy [7]

<span>peristalsis is the involuntary, progressive, rhythmic contraction of the muscle in the wall if the esophagus propelling a ball of food down toward the stomach</span>

4 0

3 years ago

Read 2 more answers

Human populations in low-UV environments tend to have more lightly pigmented skin. One explanation is that the selective pressur

nikdorinn [45]

Answer:

Lightly pigmented people tend to be at higher risk of vitamin D deficiency

Explanation:

BACKGROUND KNOWLEDGE:

Human skin is the largest organ of the body which makes boundary line between environment and internal conditions. Human skin cell produces pigment called melanin when ever it is subjected to Sun. More the melanin pigment produced more will be the skin darkens. Ultraviolet (UV) radiations also come from Sun and responsible for more pigmentation.

ANSWER EXPLANATION:

According to the question darkly pigmentation only occurs when their is high level of UV radiations. High level of UV radiations are also responsible for Vitamin D production.

People with lightly pigmented means that there environment has low level of UV radiations which are the requirement of Vitamin D production. Hence due to low UV radiations peoples with light pigmentation's are also be at higher risk of vitamin D deficiency

7 0

3 years ago

A major disturbance that the ecosystem was able to recover completely from.

kolezko [41]

Hello. Your question is incomplete. However, I managed to find a question exactly like yours on the internet and managed to realize that you forgot to say that your question asks you to give an example of the statement presented above.

Answer:

A major disturbance from which the ecosystem was able to recover completely was the disease that almost wiped out all of Ireland's potato in 1840.

Explanation:

You may have heard of the Irish Potato Famine, which was a time when the Irish population lived very difficult days, after an illness that almost decimated the country's potato plantations.

The potato was the main source of food for the Irish, but in 1840, a fungus called Phytophthora infestans, managed to infect almost all potato plantations in the country, preventing the potato from being harvested and could be consumed. This created major economic and social problems in Ireland, as people suffered from hunger, poverty and the diseases that arose, which caused many Irish people to immigrate to other countries, or to die.

The fungus plagued the ecosystem for years and only started to decrease in intensity in 1850, once the ecosystem started to recover. Currently, although the pest still exists, the Irish ecosystem is completely recovered and the pest is controlled and is unable to make such an impact.

8 0

3 years ago

Antibodies are composed of two types of peptides, heavy chains and light chains. One of the major classes of antibody molecules

timurjin [86]

Answer and Explanation:

a. form the antigen-binding site ⇒ both chains

The antigen-binding site is formed by one hypervariable region of the light chain (VL) and one hypervariable region of the heavy chain (VH). So, both type of chains contributes to antigen recognition.

b. contain multiple variable domains ⇒ none

Both chains - light and heavy - contain <u>only one</u> variable domain (VL and VH).

c. are found in the Fab fragment ⇒ both chains

The Fab fragment is composed of portions of both light and heavy chains: each portion contains one variable domain and one constant domain. The Fab fragment binds specifically the antigen.

d. are found in the FC fragment ⇒ heavy chains

The Fc region is composed of portions of heavy chains (CH² and CH³), so it contains constant domains.

e. contain only one constant domain ⇒ light chains

Each light chain contains one variable domain (VL) and one constant domain (CL).

f. contain multiple constant domains ⇒ heavy chains

Each heavy chain contains three constant domains: CH¹, CH² and CH³.

g. contain only one variable domain ⇒ both chains

Both light and heavy chains contain one variable domain. The difference is given by the number of constant domains: light chains have 1 constant domain while heavy chains have 3 constant domains.

8 0

3 years ago

A wildfire burns a region of a healthy grasslands ecosystem. Which climax community will MOST LIKELY arrive in the burned region

Reptile [31]

Answer:

lichens and bryophytes[secondary seccession]

Explanation:

after the wildfire, the area would bee too dry and therfore it'll lead to a xerarch succession. lichens and bryophytes would be the climax communities.

7 0

3 years ago

Read 2 more answers