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.
A parallelogram is a four-sided shape in which the opposite sides  are parallel.   A â¦ rectangle (and a square) is a four-sided shape in which the  opposite sides are parallel and all corners are 90 degrees. The  corners of a parallelogram can be 90 degrees but can also be  different angles. Therefore, rectangles and squares are subsets of  a parallelogram. 25 people found this useful.