Answer:
a. the virus must be able to cross-link red blood cells directly.
Explanation:
Viral hemagglutination assay is a method which is used for the quantification of the relative concentration of the viruses.
The principle on which the hemagglutination assay works is as follows:
- There are sialic acid receptors present on the surface of the red blood cells which will bind to the haemagglutinin glycoprotein present on the surface of the viral particle.
- Due to the binding of the sialic acid receptors with haemagglutinin particle there will be cross-linking of the red blood cells by the viral particles and a lattice formation will take place.
- The lattice will remain suspended in the solution however if the concentration of the virus particles will be less, the lattice will settle down in the well.
Thus, this method allows knowing the relative concentration of the virus.
<em>Due to its basic principle of cross-linking this method works well for only a few viruses such as influenza virus. </em>
Answer:
D
Explanation:
Vegetation on soil protects the soil from erosion because its roots and root hairs help bind the soil particles together. This occurs mechanically by binding soil into crumbs and also chemically by providing organic matter that binds the soil particle into humus that holds moisture. The soil becomes heavy to be carried off by wind erosion. Trees also break the down flow of water hence reducing the capacity of runoff to carry soil sediments.
According to the Doppler effect, the sound of a police car siren is louder and high pitched as it approaches the observer.
Because Evolution, theory in biology postulating that the various types of plants, animals, and other living things on Earth have their origin in other preexisting types and that the distinguishable differences are due to modifications in successive generations
Active transport requires energy from the cell. It occurs when substances move from areas of lower to higher concentration or when very large molecules are transported. Types of active transport include ion pumps, such as the sodium-potassium pump, and vesicle transport, which includes endocytosis and exocytosis.
