Best Answer: Crossing-over is another name for recombination or physical exchange of equal pieces of adjacent non-sister chromatids. When crossing-over occurs chromatids break and may be reattached to a different homologous chromosome. This occurs during Meiosis 1 / Prophase 1. Synapsis occurs when homologous chromosomes form tetrads and crossing-over or recombination takes place.
The best time to apply castor oil is at night, preferably couple of hours before bed time. While it is perfectly fine to use them during day time, there is a big advantage in applying them at night as this allows more time to saturate and start the process which aids in growing eyelashes.
It is an awesome remedy for hair growth as well. Mixing with castor oil has also been proven to be a fantastic remedy to grow eyebrows faster. It works as an add on and provide moisture to the skin. 1  Take some Vaseline and mix it with some castor oil.  Apply it on the eyebrows and leave it overnight.