Natural Sciences (NatSci for short) is an amalgamation of the various sciences; as a scientist, you choose 4 modules out of a broad range of choices in the first year, 3 in second year, and finally a specialist subject in third year. You may have the option to continue for a fourth year, depending on your subject, to obtain a Masters.
The beauty of studying Natural Sciences in Cambridge is that although you may be in the Biological part of NatSci, it does not mean you restrict yourself from any of the Physical modules! It is not unusual to find a Physics NatSci doing Biology of Cells, or a Biology NatSci studying Physics and/or Chemistry; the flexibility and range allows for you to tailor the course to suit your interests, and the interdisciplinary focus on each module means that you may discover many subjects cross-over each other.
From Physics, Earth Sciences to Physiology, scientists studying at Cambridge will find themselves continuously challenged on paper and in the lab. If you possess an inquisitive spirit that delights in unravelling the secrets of the natural world, then NatSci is for you!