<span>B is the correct answer. The beginning of DNA replication occurs with the unwinding of the DNA helix by a special enzyme. The two strands that form the helix then create a replication fork. The two strands are then oriented differently, one becoming the 'leading strand' and one the 'lagging strand'. </span>
Number <u>3</u> is the chloroplast. The chloroplast helps the plant obtain food by <u>photosynthesis</u>. Number <u>1</u> is the central vacuole. The central vacuole helps a plant maintain its structure by <u>turgor pressure</u>.