My mother and father are both scientists it must have been my just need to become interested in biology. How do you explain what type of run on sentence this is?

- Fused sentence.

Explanation:

'Fused sentence' is described as the type of run-on sentence in which two independent clauses run together (one after another) without any coordinating conjunction or marks of punctuation to keep the two ideas separate.

The given sentence exemplifies 'fused sentence' as it justifies the above definition where two independent clauses ('My mother and father are both scientists' and ' it must have been my just need to become interested in biology') run together without employing any punctuation or conjunction to link them. The correct version could be:

'My mother and father are both scientists, so it must have been my destiny to become interested in biology.'

'My mother and father are both scientists; it must have been my destiny to become interested in biology.'