Hat is the horizontal line present across the front teeth of this skeleton and what does it represent?

What environmental cues and landmarks do the geese use to determine the timing and direction of their migration over the mountains? how do they find their way?

Consider the activity and specificity of the three enzymes. pepsin is most active in the human and to digest

An adult inhales about 6.0×10−4 m3 of fresh air during a breath. only 20% of fresh air is oxygen. assume the pressure in the lungs is 1.0×105 paand the air is at a temperature of 300 k. how many oxygen molecules are in each breath? a. 1.4x10^23 b. 2.9x10^21 c. 4.9x10^-4 d. 2.9 x10^25