Biology Help!

Edward Jenner is considered the founder of vaccines in the western world. In 1796, he inoculated a 13 year-old-boy with the virus that caused cowpox. Since cowpox and smallpox are closely related, the result was a demonstrated immunity to smallpox. Later, the first smallpox vaccine was developed. During the next two centuries, systematic implementation of mass smallpox immunizations culminated in its global eradication in 1979.
Using the cowpox virus to create a virus for smallpox ...

A) ...allowed only expectant mothers to pass the immunity on to their unborn children.
B) ... induced a secondary response because the body immediately recognized cowpox as smallpox due to the similarities in their genetic blueprints.
C) ...induced a primary immune response and immunological memory. Because of this, an encounter with the pathogen would trigger a rapid and strong secondary response.
D) ...allowed the virus to lie dormant within the cells of the person. When introduced to the virus again, the body could use the dormant pathogen as a point of reference.

enzyme active site and substrate specificity

enzymes bind with chemical reactants called substrates. there may be one or more substrates for each type of enzyme, depending on the particular chemical reaction. in some reactions, a single-reactant substrate is broken down into multiple products

it has to be understood that the sea water contains a huge amount of sodium and chlorine ions and if they enter the cell of the atlantic cod fish, the cell will shrivel and the fish will die. to avoid such a condition, the fish uses active transport for the purpose of removing the ions against the gradient.

explanation:

the atlantic cod is not a maritime osmoconformer. its native application of salts is less than that of the seawater it lives in. it is continually falling water from the gills to the ocean via osmosis.

countering that, the fish is going to be swallowing seawater. but since its internal collection of salts is lower than seawater, the fish will want to go free of excess salt, and since that's going upon a gradient, then active transport, requiring energy, must be used to pump out the salt. much marine fish use the organs to filter out the salt and these fish discharge very straight urine.