Answer:
d.The wing-assisted incline running theory postulates that wings were initially used to maintain balance while climbing up slopes.
Explanation:
Two theories were given to explain the origin of avian flight. The top-down theory suggested that the birds' ancestors were tree dwelling species. They took help of wings to glide from tree to tree in order to avoid predator or catch prey. The bottom up theory suggested that the birds' ancestors were ground dwelling species. They took help of wings to maintain a balance and provide a lift for efficient running.
Wing-assisted incline running was a mixture of both the above theories and gave a balanced view point. According to it, birds' ancestors used wings to maintain a balance while running up inclined slopes. The wings helped them to save energy while scaling slopes and eventually a flight mechanism was also developed.
... a Y chromosome from the father.
Temperature, pressure and composition.
The correct answer is: stratosphere.
This is because their temperatures are rising instead of decreasing.
There are 4 primary layers of the atmosphere on Earth:
Troposphere (6-20km), the layer that we live in, where the weather occurs. Only nitrogen and oxygen present.
Stratosphere (20-50 km), where the airplanes fly, contains the ozone layer, which absorbs harmful radiation from the sun.
Mesosphere (50-85 km), the coldest region of Earth’s atmosphere (-100 C), protective layer
Thermosphere (80-690), the hottest (1500 C) and the thickest layer which consists of the ionosphere and the exosphere.
The red line is the wavelength
The blue line is the amplitude
