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:
part of the male reproductive system needs to have temperature 1Â° C- 3Â° C lower than the internal body temperature and produces sperm called scrotum part of the male reproductive system keeps the testes 1Â° C- 3Â° C cooler than the normal body temperature and function as a protective sac that holds the testes epididymis part where sperm mature until they are capable of swimming and moving