Source of minerals Rocks, ores and gems A rock is a mass of one or more minerals or mineral substances. Some rocks, such as limestone or quartzite, are composed primarily of one mineral – calcite or aragonite in the case of limestone, and quartz in the latter case. Other rocks …

The general theory of evolution is that organisms have changed over time. Usually, natural selection keeps things the way they are. This is stabilizing selection (Figure 17.9a and b, and Figure 17.10). Agouti rabbits are the best adapted rabbits to survive predation, so the agouti allele remains the most common …

What is Micro-propagation? Micropropagation is a method to produce genetically identical plantlets by using in vitro tissue culture techniques. More specifically, Micropropagation refers to the in vitro multiplication and/or regeneration of plant material under aseptic and controlled environmental conditions to produce thousands or millions of plants for transfer to the …