The concept of multi-directional development suggest that when change is gradual it is an example of

Continuity

Explanation:

According to my research on studies conducted by various scientific professionals, I can say that based on the information provided within the question this is an example of Continuity. This refers to the uninterrupted but gradual constant change during a long period of time. Just like when a tortoise continues to grow during it's 150 year lifespan.

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the answer would be c. sediment buildup on continental slope

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