We typically don't think of cancer as an issue outside of humans (or maybe our pets). Yet cancer is ubiquitous in multicellular animal life (technically speaking, metazoans of the Kingdom Animalia in the supergroup Opisthokonta). It occurs even in short-lived "simple" forms like hydras, whose cancers exhibit metastasis (mobility of cancer cells, loosely), and whose tumor-related genes are orthologues (in the same gene family, loosely) to those in mammals! Furthermore, it has been shown that such cancers are also failures of regulatory networks. You need to think back to the principles of Occam's razor (when possible - a single explanation is favored, relative to many ad hoc explanations) to identify the correct statement(s) below. SELECT ALL THAT APPLY--MORE THAN ONE ANSWER POSSIBLE.
A. The Atavistic Hypothesis could account for this broad range of organisms exhibiting cancer.
B. If the Atavistic Hypothesis is correct, this plus the observation mentioned in the question, lead to the hypothesis that many developmental pathways have been inherited (and perhaps modified) in multicellular animals as diverse as monkeys and hydras.
C. Neither of these are good hypotheses as different cancers have different effects.
Atavism states that it is the biological modification whereby an ancestral trait has been lost and is reappeared in the present generations. This and the explaination given in the question which tells that hydras exhibit the phenomenon of metastasis and also these genes are orthologous to those of mammals gives us the idea that the atavistic hypothesis is correct as metastasis is being regenerated or seen in the cancer patients and also the present explaination in the given paragraph tells that the developmental pathways are all inherited as the genes are orthologous. Hence the correct answer possible is:
B. If the Atavistic Hypothesis is correct, this plus the observation mentioned in the question, lead to the hypothesis that many developmental pathways have been inherited (and perhaps modified) in multicellular animals as diverse as monkeys and hydras.
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We typically don't think of cancer as an issue outside of humans (or maybe our pets)....