HELP PLEASE Why don't vaccines that are made of living cells cause disease? *
O The pathogen's antigens have been removed.
O The pathogen has had its genetic material removed.
O The pathogen is attacked by memory B cells.
O The pathogen has been weakened.

option a is correct i.e.

explanation:

in context to the membrane of nerve impulse, the outer membrane of neuron is semi permeable that is only sodium ions can pass through the membrane i.e. smaller ions can pass through the membrane while larger ions cannot pass through it.

"d.) carbon dioxide and hydrogen sulfide"

the tricuspid valve is present between right atrium and right ventricle