A biology major studies the science behind living organisms. This includes the origin and history of animal and plant life, and their characteristics, function, processes and habits.
Biology is the study of living things from tiny micro-organisms, plants and animals to human beings. You will learn about genetics, environmental biology, plant biology, zoology (including animal behaviour), biochemistry and molecular biology with options to specialise as your interests develop.
With a BS in Bio, you'll be competing against a lot of people for relatively few jobs. It's not a great scenario to be in. You'll want to get another certification, skill, or graduate degree that is more marketable/in demand. It isn't a useless major, but it definitely needs something extra to supplement it.
Biology is certainly a hard major but not quite as difficult as other STEM majors such as physics or chemistry. Most students find a biology degree difficult to pursue because it has an extensive syllabus, lots of lab work, several challenging concepts, unfamiliar vocabulary, and lots of things to memorize.