Crossing over occurs at the four-strand stage when two homologous chromosomes, each consisting of a pair of sister chromatids, are paired. Each crossover involves just two of the four strands and generates two recombinant strands.
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Answer:
This question is not well placed. It should be " a relationship between two organisms in which both benefit is called".
The answer is SYMBIOSIS
Explanation:
Living organisms tend to interact with one another in their natural environment. This interaction are of different types depending on the effect on the involved organisms. One of those interactions is SYMBIOSIS. Symbiosis is a relationship between two organisms in which both of the organisms benefit from one another.
An example is the relationship between the "CATTLE AND EGRET". The cattle provides food for the egret when they feed on the insect parasites on their body while the egret helps the cow get rid of detrimental parasites.
What are the two primary sources of energy for the earth
His parents were both heterozygous for hyperthermia and had the recessive gene. (hope this helps)