Concept:
The doctrine of separation of powers seeks to distribute governmental authority among different organs of the State. India follows a flexible model rather than a strict separation.
Step 1: Evaluating the Assertion.
Under the Indian constitutional scheme, the Executive is drawn from the Legislature and remains accountable to it. Similarly, certain powers of the Judiciary, Legislature, and Executive overlap.
Therefore, the Assertion is true.
Step 2: Evaluating the Reason.
The Constitution establishes a system of checks and balances. Each organ exercises certain controls over the others to prevent concentration of power.
Therefore, the Reason is also true.
Step 3: Determining the relationship between A and R.
The existence of checks and balances and limited functional overlap is precisely the reason why India does not follow a rigid separation of powers.
Hence, the Reason correctly explains the Assertion.
\[
\boxed{\text{Both A and R are true and R correctly explains A}}
\]