Dec. 18 (UPI) --New research shows bird pairs that coordinate their singing and wing movements are better able to get their message across. Just as facial cues and hand gestures make human speech more ...

Before starting this guide, it may be helpful to read the guide from M1 on coordinates and graphs. To solve the equations graphically, the two lines 𝒚 = 𝒙 + 1 and 𝒚 = 2𝒙 - 1 are drawn on the same ...