Three types of parasites can cause disease in humans. They are protozoa, carried by mosquitos, helminths, such as roundworm, and ectoparasites, for instance lice and bed bugs. Parasites are organisms ...

Nature classifies all trees into three main groups. Deciduous trees shed leaves seasonally. Evergreen trees remain green year-round. Coniferous trees reproduce using cones. These categories explain ...

The history of life stretches back untold eons. Today, there is a staggering array of organisms on Earth, with more species being discovered every year. The complexity of life, from the smallest ...