Assertion : Leucosolenia shows ascon type of canal system
Reason : In Leucosolenia water passes through ostia `rarr` spongocoel `rarr` osculum

Options

A. If both the assertion and the reason are true and the reason is a correct explanation of the assertion
B. If both the assertion and reason are true but the reason is not a correct explanation of the assertion
C. If the assertion is true but the reason is false
D. If both the assertion and reason are false

Answer

A

Explanation

Leucosolenia shows simplest (ascon) type of canal system. In this, surrounding water enter the canal system through ostia. This water of sea enters into the spongocoel and pushed out readily thorugh osculum. Course taken by the water current in the body of spongs may be shown as under.
Ingressing `underset("Ostia")overset("Through")(rarr)` Spongocoel `underset("Osculum")overset("Through")(rarr)` To outside