DNA replication is considered semiconservative because after replication each daughter DNA molecule contains:

• A. Two newly synthesized strands and no parental strands
• B. One parental (old) strand and one newly synthesized strand
• C. A mixture of parental and new DNA segments within each strand due to random fragmentation and rejoining
• D. Two parental strands and no newly synthesized strands

Answer: (B)

Verified step by step guidance

1. Understand the concept of semiconservative DNA replication: it means that each new DNA molecule consists of one original (parental) strand and one newly synthesized strand.
2. Recall the structure of DNA: it is double-stranded, with each strand serving as a template during replication.
3. During replication, the two parental strands separate, and each serves as a template for the synthesis of a complementary new strand.
4. As a result, each daughter DNA molecule contains one strand from the original DNA molecule and one newly made strand.
5. This explains why the correct description of semiconservative replication is that each daughter DNA molecule has one parental strand and one newly synthesized strand.