Pyroclastic rocks are the product of explosive volcanism. They are often felsic (high in silica). Pyroclastic rocks are often the result of volcanic debris, such as ash, bombs and tephra, and other volcanic ejecta.henocrysts are crystals that are larger than the matrix and are identifiable with the unaided eye. Rhomb porphyry is an example with large rhomb shaped phenocrysts embedded in a very fine grained matrix. Volcanic rocks often have a vesicular texture caused by voids left by volatiles trapped in the molten lava.
July 9, 2014. Frozen sperm must be stored in extremely cold temperatures (-196 F), but in order to ensure that the fewest possible sperm are damaged, the freezing must be gradual. Generally, the following procedure is followed:
But, the proper temperature needed to keep the sperm viable is within narrow margins. Therefore, the scrotum, housing the testicles, will descend or contract toward the body to control the temperature necessary for healthy sperm production.Source(s): Professional Wildlife Cinematographer, Photographer, & Naturalist 38 years.BWANA Â· 7 years ago. Thumbs up.ut, the proper temperature needed to keep the sperm viable is within narrow margins. Therefore, the scrotum, housing the testicles, will descend or contract toward the body to control the temperature necessary for healthy sperm production.