Many species of fungus exist in the environment, but only some cause infections. The primary source of most infections is soil. Fungal infections can be acquired by inhalation, ingestion, or through the skin (for example, through a cut or wound).
Squares are quadrilaterals in which all four sides and all four angles have equal measurements. Rectangles have four angles with equal measurements, and the opposite sides also have equal measurements. All squares are rectangles, but not all rectangles are squares. Trapezoids have exactly one pair of parallel sides. Rhombuses have four sides with equal measurements, and opposite pairs of sides are parallel. All rhombuses are parallelograms, but not all parallelograms are rhombuses. All squares are rhombuses, but not all rhombuses are squares.
These types can be grouped into three main types of quadrilaterals: general, parallelogram and trapezoid. A rectangle and a rhombus are also parallelograms because they have two pairs of sides that are parallel. A square is also a rectangle because it has four right angles and is a parallelogram because it has two pairs of parallel sides.