The three most universal features defining modern molluscs are a mantle with a significant cavity used for breathing and excretion, the presence of a radula (except for bivalves), and the structure of the nervous system.
Answer:
B. axon hillock
Explanation:
The axon hillock is the junction where the cyton connects with the axon. There is only one axon hillock in the neuron and it is a triangular depression of cell boy to the axon. The axons receives impulse from cyton carry to the different parts of the body. The axon hillock is also called initial segment. Because action potential starts here.
Myelin sheath is the cover or layer around the axon and helps in saltatory movement of impulse. The propagation of impulse is fast in myelinated neurons than the non-myelinated neurons.
The neurolemma is the neural membrane of the neurons. It is like the plasma membrane of the cell. The outer covering of neurons is called neurilemma.
Axon collateral is the end of the axon where axon terminals arise. They carry impulse and transmit to the synapse.
Answer:
A. it is found on articular surfaces of bone
Streams that flow beneath melting glaciers leave long ridges of layered sediments, known as Esker. Eskers are formed within ice-walled tunnels by streams which flowed within and under glaciers. They tended to form around the time of the glacial maximum when the glacier was slow and sluggish and after the retaining ice walls melted away, stream deposits remained as long winding ridges.
