Crossing over happens in Meiosis 1 only. In Prophase 1 a cells chromatin (chromatin = chromosomes that have not condensed yet) condense and pair up forming homologous chromosomes (paired = XX (2 chromosomes together)). When this happens segments/ alleles of the chromosomes pairing up swap over. This creates genetic diversity as each chromosome is different, it has parts from its pair. This leaves every chromosome unique and individual.
I hope this helps, sorry some of the vocab is rather technical. By the way I would suggest watching the
'Crash Course: Meiosis' on YouTube, this really helped me when I was learning this topic. :D
Anearthquake is what happens when two blocks of the earth suddenly slip past one another. The surface where they slip is called the fault.
or
An earthquake is the result of a sudden release of stored energy in the Earth's crust that creates seismic waves.
Earthquakes are accordingly measured with a seismometer, commonly known as a seismograph.
The magnitude of an earthquake is conventionally reported using the Richter scale or a related Moment scale
An earthquake is caused by tectonic plates getting stuck and putting a strain on the ground.
The strain becomes so great that rocks give way by breaking and sliding along fault planes.
Earthquakes may occur naturally or as a result of human activities.
Smaller earthquakes can also be caused by volcanic activity, landslides, mine blasts, and nuclear experiments.
Alleles are versions of a gene that will express different qualities. Multiple alleles would mean that a gene has many variations; for example, there a multiple alleles for eye color: blue, green, brown, etc. The opposite would be a gene with just two variations; an example would be simple pea plants which can have smooth or wrinkled pods.
Hope this helps!!
Helicase. It unwinds and breaks the hydrogen bonds so other molecules can move on to the DNA strand and begin replication.
Answer:
lion as a highly social animal present a number of issues when it comes to knowing parentage: there can be multiple males in a group mating with many of the female, females raise the young of other pride member.
