The phrase "individual molecules" refers to a single unit or building block of a substance. It means looking at each molecule separately, without considering the larger group it may be a part of. Full definition
The computing power and programming expertise to accurately simulate the behaviour of individual molecules in this way has only become available in the past decade. (sciencedaily.com)
They then tested the contributions of samples from breast milk as well as individual molecules in both animal and cellular models of infection, measuring the length of time until resolution. (sciencedaily.com)
The precise positioning of individual molecules with respect to one another is fundamentally challenging. (sciencedaily.com)