Which of the following BEST explains the timing of the classical pathway of complement fixation, relative to the other pathways of complement fixation, against a pathogen in an individual who hasnever been exposed to said pathogen?

A. No target for C1qrs exists on the surface of the pathogen in the earliest stages of theresponse to it.

B. The chemical environment of the pathogen's surface favors the spontaneous activation ofsoluble C3 immediately upon exposure to the pathogen.

C. C1qrs immediately recognizes carbohydrate antigens on the surface of the pathogen, allowing for rapid formation of the C4b2a C3 convertase.

D. The pathogen expresses one or more factors on its surface that act as negative regulators ofC3 convertase formation.

E. None of the above

Explanation:

1. There are 3 pathways of complement activation:

i) the classical pathway;

ii) the MB-lectin pathway; and

iii) the alternative pathway.

2. The classical complement pathway;  for activation, it requires antigen(Ag) antibody(Ab) complexes.

3. While the other pathways can be activated by various ways.

as here,  No target for C1qrs exists on the surface of the pathogen in the earliest stages of the response to it.

q: compare the parts of a cell and the cell as a whole to another common nonliving system (i.e., a car, a city,

a:

comparing this to the inside of a food building/company.

all cells are surrounded by a plasma membrane, which protects the cell from its environment, keeping toxic substances out of the cell. it regulates which molecules are allowed to enter and exit the cell.

regulates all cell activity such as cellular metabolism, and growth in addition to storing and maintaining the cell's dna for transcription and replication. determines what proteins to make.

contains the organelles; site of most cell activity

the place where ribosomes do their working activity.

builds the proteins.

prepares proteins for use or export.

responsible for breaking down and absorbing materials taken in by the cell.

maintains cell shape.

transforms one form of energy into another.

humans can cause extinction of a species through overharvesting, pollution, habitat destruction, introduction of invasive species (such as new predators and food competitors), overhunting, and other influences. explosive, unsustainable human population growth is an essential cause of the extinction crisis.

explanation:

i didn't have the answer choices , but i tried my best.