Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other.
This question related to the Doppler effect, which states that the incident frequency of waves from a moving source is different from the actual frequency. The point where the actual frequency is observed is when the source is right next to the observer.
Pathogens are any form of a disease causing bacteria, virus or any other microorganism. When they infect an organism, that organism now has to allocate precious resources in the form of energy in order to fend off the infectious microorganisms. In some other cases, an infection could be fatal to an organism completely and "stability" wouldn't really be the biggest worry for that organism.
In conclusion, if you're talking about a larger, more evolved organism with a working immune system. Pathogens require a lot of energy to fight, and for some small organism without a developed immune system, pathogens could throw them off completely.
Answer:
What can be noticed about the ligands and their receptor is that the configuration of both coincide, as a key would with its lock, which demonstrates the specificity of a receptor by its ligand.
Explanation:
A <u>ligand</u> corresponds to a molecule considered a signal or a messenger, while the <u>receptor</u> is a protein on the cell surface, with the capacity to accept a ligand.
Ligands and receptors constitute pairs that complement each other, so that <u>each receptor can bind to a specific ligand</u>, similar to what happens with a key and a lock.
Once the ligand-receptor complex is formed, changes occur inside the cell, which define a certain effect.