Statement I : Adjournment is a short recess within the session of the Parliament ordered by the Presiding Officer of the House. Statement II : When the Presiding Officer adjourns the House without fixing any date or time of the next meeting of the House, it is known as adjournment sine die.

Statement I is true as an adjournment suspends the work in a sitting for a specified time, such as hours, days, or weeks, and is ordered by the Presiding Officer of the House [c1, c3]. Statement II is also true; 'adjournment sine die' occurs when the House is adjourned without fixing a specific date or time for reassembly, effectively terminating the sitting for an indefinite period [c1, t1]. While both statements are individually correct and describe related parliamentary procedures, Statement II is not the 'explanation' of Statement I. Statement I defines a standard adjournment (which has a fixed return time), whereas Statement II defines a specific, different type of adjournment (sine die). They are distinct procedural actions taken by the Presiding Officer rather than one being the causal reason or logical derivation of the other [c1, t5].

Sources

1. [1] Indian Polity, M. Laxmikanth(7th ed.) > Chapter 23: Parliament > Adjournment > p. 236
2. [2] Laxmikanth, M. Indian Polity. 7th ed., McGraw Hill. > Chapter 33: State Legislature > Adjournment > p. 341