The avian cardiovascular system is able to quickly respond to changes in levels of activity (e.g., resting vs. flying) via changes in heart rate, cardiac output, & blood flow (by vasocontriction and vasodilation of vessels).
A square is a quadrilateral with all right angles and all equal sides. A square is also a parallelogram, a rectangle, and a rhombus and has all the properties of all these special quadrilaterals. Figure 3 shows a square. Figure 3 A square has four right angles and four equal sides. Figure 4 summarizes the relationships of these quadrilaterals to one another.
up vote 6 down vote. A rectangle is considered a special case of a parallelogram because: A parallelogram is a quadrilateral with 2 pairs of opposite, equal and parallel sides. A rectangle is a quadrilateral with 2 pairs of opposite, equal and parallel sides BUT ALSO forms right angles between adjacent sides. share | cite | improve this answer. answered Jun 29 '14 at 16:52.