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.
One special kind of polygons is called a parallelogram. It is a quadrilateral where both pairs of opposite sides are parallel. There are six important properties of parallelograms to know: 1  Opposite sides are congruent (AB = DC). 2  Opposite angels are congruent (D = B). 3  Consecutive angles are supplementary (A + D = 180Â°). 4  If one angle is right, then all angles are right. 5  The diagonals of a parallelogram bisect each other.