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:
It is heat sensitive and cannot survive in high temperature. In the man's testicles, the semen or seminal fluid provides a favorable environment. Here, the seminal fluid allows the sperm to be motile and in constant temperature. Inside the body, sperm lives for up to 74 days. The main reason why male's testicles are hanging further away from the man's body is that to protect the sperm from the heat of the body. Sperm may also die due to the person's negative lifestyle. Alcoholism, smoking, drugs and others can affect sperm survival rate.