1 Ganglia-groups of neuron cell bodies that lie peripheral to the central nervous system in vertebrates. 2  Bipolar neurons-cell body located near the middle of the axon; characteristic of retinal neurons. 3  Unipolar neurons-cell body lies off to one side of axon; characteristic of sensory neurons.
The principal host for diamonds are rocks formed in the earth's mantle that are known as eclogite and peridotite that are carried to the earth's surface in magmas known as kimberlit e and lamproite.
Most natural diamonds are formed at high temperature and pressure at depths of 140 to 190 kilometers (87 to 118 mi) in the Earth's mantle. Carbon-containing minerals provide the carbon source, and the growth occurs over periods from 1 billion to 3.3 billion years (25% to 75% of the age of the Earth).