The answer is C.
A virus is made up of or consists of a nucleic acid in varying quantity which may either be RNA or DNA.
The nucleic acid is surrounded by a protein shell called a capsid. The word capsid comes from the Latin word capsa which means box.The capsid and the nucleic acid within it are together referred to as nucleoprotein.The capsid is made up of small sub units called capsomeres.
In many viruses, the nucleoprotein makes up the whole virus. More complex viruses have one or more further enclosing structures also made mostly of protein. These structures are referred to as envelopes and each envelop is specific to a particular virus.
They're called endorphins!
Answer:
you didnt post the diagram
Explanation:
A relatively small blood pressure gradient is generally insufficient to move blood through the veins under given conditions, thus venous return must be facilitated by valves within veins and two "pumps." ... As skeletal muscles contract, veins are squeezed to help propel the blood toward the heart.
Answer:
LD50 (median lethal dose)
Explanation:
- Whenever one needs to quantify the virulence of a pathogen then this is done by using a set of laboratory animals.
- LD50 (median lethal dose) is an important indicator of virulence.
- LD50 is defined as the number of pathogens that are required to kill 50% of the total infected animals.
- For the calculation of LD50, the animals are infected with a known number of pathogens and then a graph is plotted for the percentage of animals killed against the concentration of the pathogen used for infection.<em> The point at which the graph indicates the death of 50% animals, the corresponding concentration of inoculation of a pathogen is taken as the LD50 of that particular pathogen. </em>
