You have begun work on a new experiment determining exactly how certain neurotoxins affect the nervous system. after running multiple tests studying a specific neurotoxin that affects synapses, you discover that the neurotransmitters are still being released, but they are not having an effect. what is the neurotoxin most likely doing? a. blocking the synaptic vesicles on the postsynaptic cell. b. blocking the synaptic vesicles on the presynaptic cell. c. blocking the receptors on the postsynaptic cell. d. blocking the receptors on the presynaptic cell.

When looking at a Neuromuscular Junction (NMJ), we know that neurotransmitters (NT) are released from the presynaptic cell and they then bind to the receptors that are located on the postsynaptic cell - this causes the effect of the NT being released.

So we are told that NT are still being released, however they are not having an effect. This would mean that they are probably being blocked by something - in this case, it seems that the neurotoxin is the culprit in the blocking of these receptors.

Therefore, if the NT cannot bind to the receptors on the postsynaptic cell, they are not going to have any effect, no matter how much NT is being released.

So the answer in this case is: The neurotoxin is most likely C) Blocking the receptors on the postsynaptic cell.

answer and explanation;

volcanic rocks are igneous rocks which form from lava, molten rock which has been thrust out of a volcano onto the surface of a rocky body such as an asteroid, planet, or dwarf planet.  

plutonic rocks are igneous rocks which form from subterranean chambers of molten rock or magma. plutonic rocks make up the base of continental crust as well as oceanic crust. their slow rate of formation causes them to be coarse grained since there is plenty of time for large crystals to form before the magma solidifies into rock.

the textural difference is that plutonic rocks are more coarse grained than volcanic rocks. plutonic rocks are coarse grained while volcanic are fine grained ; glassey or fragmental. since fine and coarse are adjectives the decision as to whether a rock is fine or coarse grained is generally made on the bases of whether or not the individual crystals can be seen in most if the rock.