Mitochondria and chloroplasts are unlike most other organelles in retaining a trace of genetic independence from the nucleus. Evaluate the following Assertion and Reason on why they are termed semi-autonomous.

• Assertion (A): Mitochondria and plastids are described as semi-autonomous organelles.
• Reason (R): Both organelles possess their own double-stranded circular DNA, 70S ribosomes, and the machinery to synthesise some of their own proteins, but still depend on nuclear genes for many other proteins.