Many great rivers flow toward the equator. The sediments that they carry, increases the time of rotation of the earth about its own axis.
The angular momentum of the earth about its rotation axis is conserved.

Options

A. Statement I is True, Statement II is True, Statement ll is a correct explanation for Statement I.
B. Statement I is True, Statement II is True, Statement II is NOT a correct explanation for Statement I
C. Statement I is True, Statement II is False.
D. Statement I is False, Statement II is True.

Explanation

To solve the problem step by step, we will analyze the two statements provided and their implications regarding the Earth's rotation and angular momentum.

### Step 1: Understand the Statements
- **Statement 1**: Many great rivers flow toward the equator. The sediments that they carry increase the time of rotation of the Earth about its own axis.
- **Statement 2**: The angular momentum of the Earth about its rotation axis is conserved.

### Step 2: Analyze Statement 2
- The angular momentum (L) of an object is given by the formula:
\[ L = I \omega \]
where \(I\) is the moment of inertia and \(\omega\) is the angular velocity.
- Since there are no external torques acting on the Earth, the angular momentum is conserved:
\[ \frac{dL}{dt} = 0 \implies L = \text{constant} \]
- Therefore, Statement 2 is true.

### Step 3: Analyze Statement 1
- As rivers flow toward the equator, they carry sediments with them. This movement of sediments increases the moment of inertia \(I\) of the Earth about its axis of rotation.
- When the moment of inertia \(I\) increases, and since angular momentum \(L\) is conserved, we can express this as:
\[ L = I \omega = \text{constant} \]
- If \(I\) increases, then \(\omega\) must decrease to keep \(L\) constant:
\[ I \uparrow \implies \omega \downarrow \]
- A decrease in angular velocity \(\omega\) implies that the time period \(T\) of rotation increases, since:
\[ \omega = \frac{2\pi}{T} \implies T \uparrow \text{ when } \omega \downarrow \]
- Thus, Statement 1 is also true.

### Step 4: Conclusion
- Both statements are true. Statement 2 provides a correct explanation for Statement 1.

### Final Answer
- The correct answer is: Both statements are true, and Statement 2 is the correct explanation of Statement 1.

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