Answer: Cells have receptors because Receptors let the cell know when to let things in and out of the cell.
Explanation:
Cell receptors also called transmembrane receptors are proteins located on the surface of a cell (extracellularly) or inside the cell which receive signals that alters the functions of the cell. The functions of the cells which can be altered includes the alteration in gene transcription and the cell morphology.
Cell receptors are generally categorizes into the following groups:
--> Internal receptors
--> cell surface receptors
--> ion channel receptors
--> G protein coupled receptors
--> enzyme linked receptors
Interaction of cell membrane receptors with specific ligands that bonds to the receptors causes conformational changes in the receptor protein. This in turn, enzymatically activates the intracellular part of the protein or induces interactions between the receptor and the proteins in the cytoplasm that act as second messengers, thereby relaying the signal from the extracellular part of the receptor to the interior of the cell. This enables the cell to know when to let things in or out of it through the information conveyed.
Answer:
D. the linear velocity of the point of contact (relative to the inclined surface) is zero
Explanation:
The force of friction emerges only when there is relative velocity between two objects . In case of perfect rolling , there is no sliding so relative velocity between the surface and the point of contact is zero . In other words the velocity of point of contact becomes zero , even though , the whole body is in linear motion . It happens due point of contact having two velocities which are equal and opposite . One of the velocity is in forward direction and the other velocity which is due to rotation is in backward direction . So net velocity of point of contact becomes zero . Due to absence of sliding , displacement due to friction becomes zero . Hence work done by friction becomes zero.
1. Based on Scenario A, multiple frames will minimize re-transmission overhead and should be preferred in the encapsulation of packets.
2. Based on Scenario B, the encapsulation of packets should be in a single frame because of the high level of network reliability and accuracy.
<u>Justification:</u>
There will not be further need to re-transmit the packets in a highly reliable and accurate network environment, unlike in an environment that is very prone to errors. The reliable and accurate network environment makes a single frame economically better.
Encapsulation involves the process of wrapping code and data together within a class so that data is protected and access to code is restricted.
With encapsulation, each layer:
- provides a service to the layer above it
- communicates with a corresponding receiving node
Thus, in a reliable and accurate network environment, single frames should be used to enhance transmission and minimize re-transmission overhead. This is unlike in an environment that is very prone to errors, where multiple frames should rather be used to minimize re-transmission overhead.
Learn more about encapsulation of packets here: brainly.com/question/22471914
Formula for time
t=d/s
so…
t= 48m/4m/s
the two ms cancel each other out and ur left with s
t=12s
