Biotechnology

Let's analyze each statement:

• (A) DNA from one organism will not band to DNA from other organisms
  This is incorrect. DNA from different organisms can hybridize or bind if they share similar sequences. The ability to bind is not restricted to organisms of the same species.
• (B) Genetic engineering works only on animals and not yet successfully used on plants
  This is incorrect. Genetic engineering has been successfully used in both plants and animals. Many genetically modified plants, like Bt cotton and golden rice, have been developed using genetic engineering techniques.
• (C) There are no risk factors associated with r-DNA technology
  This is incorrect. There are several risk factors associated with recombinant DNA (r-DNA) technology, including potential ecological impacts and safety concerns related to genetically modified organisms (GMOs).
• (D) The first step in PCR is heating which is used to separate both the strands of the gene of interest
  This is correct. The first step in the Polymerase Chain Reaction (PCR) is denaturation, where the DNA is heated to separate its two strands. This is followed by cooling to allow primers to bind to the single-stranded DNA.

The correct answer is (D) : The first step in PCR in heating which is used to seperate both the strands of gene of interest.

• PCR (Polymerase Chain Reaction) is a technique primarily used for DNA amplification. It allows the production of many copies of a specific DNA segment.
• The process involves repeated cycles of heating and cooling to denature the DNA, anneal primers, and extend the DNA strands, thus amplifying the target sequence.

The correct answer is (A) : DNA amplification.