Answer: Valves in the veins
Explanation: The flow of the blood inside the body takes place through the veins and arteries. The oxygenated blood from the heart is supplied to the different parts of the body.
The blood flows from the capillaries to the venules and from there to the veins. The blood moves in the veins by the rhythmic movement of the smooth muscles in the body.
Most of the blood moves against the gravity so there is a chance that it can backflow so to prevent this there are valves in the veins known as one way valves.
The correct answer to your question is A. :)
The correct answer is "is found only in Corynebacterium diphteriae cells that have been infected with lysogenic bacteriophage β".
An exotoxin is a bacterial toxin which is secreted by the toxin in its surrounding environment.
The diphtheria exotoxin is a toxin produced and secreted by some pathogenic bacteria of the species <em>Corynebacterium diphtheriae</em>. This exotoxin is only produced by bacteria who have been infected with lysogenic bacteriophage β (a specific type of virus which infects bacteria). The reason for this is that the virus encodes the gene responsible for producing the toxin.
I think the nuclear membrane begins to break down, and the pair of chromosomes look like their are floating in the air.