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sergeinik [125]
3 years ago
11

The xylem cells are square, whereas the phloem cells are round. From which part of the stem tissue is wood made? Select one: a.

spongy mesophyll b. the cuticle c. old layers of xylem and phloem d. central parenchyma Flat leaves lose water to the environment more readily than pine needles do.

Biology
1 answer:
Andrei [34K]3 years ago
5 0

Answer:

The correct answer is option c. "old layers of xylem and phloem".

Explanation:

Wood is one important good used for construction obtained from the main substance of the outer layer of the trunk or branches of a tree. Biologically, the outer layer of the trunk of a tree is comprised of the old layers of xylem and phloem, which are dead cells that were part of the heartwood or the centre of the tree. These old layers of xylem and phloem form the outer bark structure of the tree.

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1. Although their concentration in the atmosphere is lower than carbon dioxide, ____________________ absorb Earth's outgoing rad
cestrela7 [59]

Answer:

1. Trace gases  2. Climate feedback mechanisms 3. Positive feedback mechanisms 4. Aerosols  5. Negative Feedback Mechanisms 6. Positive feedback mechanism

Explanation:

Using the knowledge of global warming as a result of climate change, we can provide the following answers to fill in the gap:

1. Trace gases

Greenhouse gases provides a natural effect known as greenhouse effects. This effect is achieved when greenhouse gases trap and absorb infrared radiation, in form of heat, thereby slowing down the loss of he into space. This effect ensures the earth remains habitable as the temperature of the earth would drop causing freezing of the earth. Life would almost not exist in the absence of this phenomenon caused by greenhouse gases. Carbon dioxide accounts for the highest percentage by volume of the total greenhouse gases found in the atmosphere. Trace gases such as argon are found in minute quantities in the atmosphere. Hey also have the ability to absorb infrared rays.

2. Climate feedback mechanisms

Climate feedback mechanism is a kind of continuous cycle that describes how the system responds to the changes it is being impacted on. The change can either produce an increase or decrease in the warming effect. There are basically 2 types of feedback mechanism: Positive and Negative feedback mechanism. A positive feedback mechanism involves changes that reinforce the increase of the temperature of the system, while negative feedback mechanisms involves processes that reduce the effect of warming, causing a drop in temperature of the system.

3. Positive feedback mechanisms

Effects that involve processes that helps in pushing the temperature of the climate system up, thereby producing additional warming effect on the initial warming trend of the system are said to be identified as Positive feedback mechanisms. Examples of such effects is melting of ice, especially as more pronounced in polar regions.

4. Aerosols

Aerosols can be in form of fine solid particles or liquid droplets suspended in the air. Examples of aerosols include dust, fog, smoke or air pollutants. They have the ability to scatter solar radiation and change the reflectivity of the earth. These effects created by aerosols have a cooling effect on the climate system, as a against the effect produced by greenhouse gases. The effects caused by aerosols are examples of negative feedback mechanisms.

5. Negative Feedback Mechanisms

An example of such effects is the effect produced by aerosols. Such effect cools the system which is opposite to the warming trend of the system.

6. Positive feedback mechanism

Decrease in surface reflectivity, and increase in surface solar energy absorption as a result of reduced sea ice would further reinforce the warming trend of the system, such change a positive feedback mechanism.

6 0
3 years ago
Select the correct answer.
KIM [24]

Answer:

C. It combines hydrogen ions in sugar molecules to release energy and form water.

Explanation:

Lastly, the hydrogen ions flow through ATP synthase to make ATP.

8 0
3 years ago
The four most abundant elements needed by the human body are carbon, hydrogen, oxygen, and nitrogen. because these are needed in
jek_recluse [69]

The four most abundant elements needed by the human body are carbon, hydrogen, oxygen, and nitrogen because these are needed in large amounts to support our cells, these are referred to as bulk elements.

Oxygen is the most essential element required by our body. The body requires oxygen in the form of gas which is inhaled by the air around us. All the cells in a human body require oxygen which is transported by the blood inside.

Cell is the most basic and fundamental unit of life. It can be of two types: prokaryotic and eukaryotic. Prokaryotic cell is the primitive one with no true nucleus and eukaryotic cell has a true nucleus and all the cell organelles. Generally eukaryotic cells require abundant amount of oxygen.

To know more about cell, here

brainly.com/question/12129097

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4 0
1 year ago
Why are grassland and forest soils good for farming?
Musya8 [376]
<span>I believe the answer is C. Grasslands and forests do not have permafrost--present in tundra and taiga so A can be eliminated. B  is not right because forests and grasslands definitely do not get TOO much rain, assuming they're not talking about tropical rain forests. </span>
6 0
3 years ago
3. The human body has devised an excellent method to keep the body pH under control. a. What principle underlies the constant pH
kumpel [21]

The normal blood pH for adult humans is 7.40, and this pH value is vigorously defended at normal body temperature

Acid base Homeostasis is the method by which body keeps a constant ph
pH is kept under check via different systems
1. Chemical system :bicarbonate buffer system(explained below )
Respiratory component :
2. Respiratory Component: The second line of dense is rapid consisting of the control the carbonic acid concentration in the ECF by changing the rate and depth of breathing by hyperventilation or hypoventilation. This blows off or retains carbon dioxide (and thus carbonic acid) in the blood plasma as required

3.Metabolic component : third line of defense is slow, best measured by the base excess,eand mostly depends on the renal system which can add or remove bicarbonate ions to or from the ECF.Bicarbonate ions are derived from metabolic carbon dioxide which is enzymatically converted to carbonic acid in the renal tubular cells.There, carbonic acid spontaneously dissociates into hydrogen ions and bicarbonate ions.When the pH in the ECF falls, hydrogen ions are excreted into urine, while bicarbonate ions are secreted into blood plasma, causing the plasma pH to rise.The converse happens if the pH in the ECF tends to rise: bicarbonate ions are then excreted into the urine and hydrogen ions into the blood plasma.




Buffers usually consist of a weak acid and its conjugate base; this enables them to readily absorb excess H+ or OH–, keeping the system’s pH within a narrow range.

Maintaining a constant blood pH is critical to a person’s well-being. The buffer that maintains the pH of human blood involves carbonic acid (H2CO3), bicarbonate ion (HCO3–), and carbon dioxide (CO2). When bicarbonate ions combine with free hydrogen ions and become carbonic acid, hydrogen ions are removed, moderating pH changes. Similarly, excess carbonic acid can be converted into carbon dioxide gas and exhaled through the lungs; this prevents too many free hydrogen ions from building up in the blood and dangerously reducing its pH; likewise, if too much OH– is introduced into the system, carbonic acid will combine with it to create bicarbonate, lowering the pH.
Example: Antacids, which combat excess stomach acid, are another example of buffers.


ECF =Extra cellular fluid




5 0
2 years ago
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