Genetic recombination refers to the process by which two DNA  molecules exchange genetic information. The three types of genetic  recombination are crossing over, conservati â¦ ve site-specific  recombination and transpositional recombination.
This produces a crystal lattice, which is commonly known as 'ice'. Ice floats because it is about 9% less dense than liquid water. In other words, ice takes up about 9% more space than water, so a liter of ice weighs less than a liter water. The heavier water displaces the lighter ice, so ice floats to the top. One consequence of this is that lakes and rivers freeze from top to bottom, allowing fish to survive even when the surface of a lake has frozen over.
Density may also refer to how closely packed or crowded the material appears to be - again refer to the styrofoam vs. ceramic cup. Density Comparison to Water: In chemistry, the density of many substances is compared to the density of water. Does an object float on water or sink in the water? If an object such as a piece of wood floats on water it is less dense than water vs. if a rock sinks, it is more dense than water. Density examples: ***See top menu bar for more examples***. Oil and vinegar salad dressing: The oil floats on the vinegar water mixture, while the solids sink to the bottom.