A covalent bond, also called a molecular bond, is a chemical bond that involves the sharing of electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs, and the stable balance of attractive and repulsive forces between atoms, when they share electrons, is known as covalent bonding.
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<span>Dreams for Survival Theory
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The dreams-for-survival theory states that dreams have helped humans evolutionarily by simulating threats, thus preparing people to fight for survival. It is also called the threat simulation theory.
<span>The theory stems from the notion that many dreams are stressful. When humans are dreaming, they are often dreaming of situations in which they need to fight to survive. This essentially provides practice for survival instincts and functions as a defense mechanism.</span>
Depending on the organism the number of chromosomes in a cell may change.
Different organisms have a different number of chromosomes, for example we have 46 and a fruit-fly(drosophila melanogaster) has 8.