How are genes and alleles related to genotypes and phenotype ?

Genes and alleles are what someone is composed of (the genotype). Dominant genes passed down from parents are more likely to show on appearance (the phenotype) although not always.

It depends on the surface of the levels. the rougher the surface, the greater is the frictional force. for rougher surfaces, you would need to exert greater force to move the object. the concept is that, you must overcome the frictional force in order to bring the object into motion. this is the reason why we add lubricants to the joints so they could easily move. this answer was on

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