PLEASE HELP 1. Although organisms often share similar genes, they may have significant phenotypic differences. Which statement explains why this may occur?

Although DNA is always expressed, the gene products may not always be used by the organism.
Gene expression is controlled by regulatory genes, regulatory elements, and transcription factors.
Not all organisms have control mechanisms, so genes may sometimes be overexpressed or not expressed at all.
The types of nitrogenous bases differ between organisms, causing gene sequences to produce different proteins.

in situ hybridization has been widely used for research applications, including clinical cytogenetics, gene mapping, tumor biology and studies of chromosome evolution.

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explanation:

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the correct answer is: b. pantala flavescens, because these organisms would have a high level of genetic variation due to sexual reproduction.  

because involves two organisms (parents) whose genetic material combines, sexual reproduction leads to genetic variation in new generations of offspring. the offspring is an unique organism, with new genome, more protected with the higher ability to adapted. this process is fundamental to evolution.