Where are the statements?
The double helix is a description of the molecular shape of a double-stranded DNA molecule. In 1953, Francis Crick and James Watson first described the molecular structure of DNA, which they called a "double helix," in the journal Nature.
False. It's not always reliable. For example, in lab mice, saccharin has caused tumors. But for humans to get cancer from saccharin, we would have to take in astronomical levels of saccharin, which we, as humans, don't do.
Replication from formation and separation of the strands
Bacteria in our gut help to protect us by crowding out some of their dangerous relatives that can cause disease. Other good bacteria have been used in medicine to create antibiotics, and others still are used in food production to make fermented foods (think sauerkraut, yogurt, kimchi and kombucha.)