Noun. 1. prefrontal cortex-the anterior part of the frontal lobe. prefrontal lobe. cerebral cortex, cerebral mantle, cortex, pallium-the layer of unmyelinated neurons (the grey matter) forming the cortex of the cerebrum. lobe - (anatomy) a somewhat rounded subdivision of a bodily organ or part; ear lobe.refrontal lobe. cerebral cortex, cerebral mantle, cortex, pallium-the layer of unmyelinated neurons (the grey matter) forming the cortex of the cerebrum. lobe - (anatomy) a somewhat rounded subdivision of a bodily organ or part; ear lobe.
1. igneous rocks: formed by the cooling and hardening of magma (molten rock) from inside Earth. 2. sedimentary rocks: formed by the compaction and cementing of layers of sediment (rock fragments, plant and animal remains, minerals from water) 3. metamorphic rocks: formed by the effect of heat and pressure on other rocks. *Earthâs crust is made-up primarily of igneous rocks.
Sedimentary rocks form when particles are deposited, compacted, and eventually cemented together over time to form a rock. Explanation: Sediments are formed by the deposition of layers of particles (which can range in size from salt molecules to avalanching rocks bigger than a house).