Answer:
A pollen tube grows from the pollen grain into the ovary
Explanation:
Water is needed for fertilization in several plant groups because the sperm needs to swim to meet the non-motile eggs of the female organs.
<em>However in angiosperms, the pollen germinates and a structure known as pollen tube which contains the male gametophyte (sperm) grows into the ovary where the ovule is located and the male gametophyte is deposited in the ovule to initiate the fertilization process.</em>
<em>Hence, water is really not necessary for fertilization in the angiosperms.</em>
The culprit is an "arctic outbreak" that originated just above the US-Canada border, which is freezing temperatures across much of the US territory.
<h3>Arctic outbreak</h3>
"Bursts" of cold air like this are usually confined to the Arctic region thanks to a series of low-pressure systems, says the NWS. However, one of these waves advanced through Canada and "escaped" to the US.
According to experts heard by Reuters, it is a vast mass of icy air in the atmosphere, which brings with it frigid temperatures - which can be prolonged if storms form.
From this information we can conclude that according to the US Weather Service (NWS), the culprit is an "arctic outbreak" that originated just above the US-Canada border, which is freezing temperatures across much of the US territory.
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Answer: glutamate
Explanation: Given the cascade of events leading to ischemia-produced brain damage, it has been suggested that glutamate antagonists administered immediately after a stroke might reduce the subsequent development of brain damage.
To know what type of transport occurred the lab and collected data are needed. As they are not present an explanation of the different transport's types, will be given.
Water, proteins, ions, and molecules of different sizes can pass through the cell membrane using different types of transports. The transport that each molecule uses depends on the concentration, size, and polarity.
We can classify the types of transport as active and passive.
Passive transport is the one that does not need energy to happen since the molecules move from a place of high concentration to a one of lower concentration. In this group, we have:
- Simple diffusion: small molecules in high concentration on one side of the membrane; move to the other side due to the difference in concentration.
- Osmosis: water passes through the membrane from a place of low concentration of molecules to one of high concentration. Water moves inside or outside the cell to valance the concentration of solutes on both sides of the membrane.
- Facilitated diffusion: uses proteins to transport large molecules, ions, or hydrophobic molecules from one side to the other. In this type of transport, we have proteins that form channels so those hydrophobic molecules can pass through the lipid membrane, and carrier proteins, which binds to a specific molecule changing their shape and transporting the molecule.
Active transport needs the<em> energy</em> to transport molecules; since it goes against the gradient's concentration. In this group, we have:
- Sodium-Potassium pump: uses ATP to move sodium outside the cell and potassium to the inside. The ions with this transport go to where they are most concentrated.
In conclusion, there are different types of transport; they depend on the concentration or type of molecule. To find out what mechanism of transport occurred in the lab, look at the components of the experiment and analyze which of these transports could be present.
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brainly.com/question/18565254
