Chemical factors: This is due to internal stimuli. Changes in the blood such as decrease in O2, increase in CO2 and decrease in PH cause impulse in the carotid artery which stimulates the respiratory centers in the medulla and cause breathing.
Mechanical factors: also called external stimuli. Compression of the fetal chest during delivery forces small amount of lung fluid out of the lungs. This increase in pressure in the chest draws air into the lungs.
Answer:
From the time of origin of life on earth has chaged many ways. The earth has also changed from the time of its origin. Both lives on earth itself are dynamic.
Different geolgical phenomena such as volcanic erruptions, tectonic movement etc., have changed the configurations of continents. These changed environment of the continents have affected the lives on the earth.
The Earth is 4.8 billion years old, while the origin of life on the earth is 3.5 billion years old. Gradually these changes have given the chaces of variations, from which the suitable organisms are selected on the earth.
Explanation:
Answer: :Total distance to be travelled = 4.4 km
= 4400 m
Diameter of wheel = 70 cm = 0.7 m
Radius of wheel= 0.7 / 2 m
Circumference of wheel = 2 * pi *r
= 2* 22*0.7 / 7* 2
= 22*0.1
= 2.2 m
No. Of revolutions = Total distance / Circumference of wheel
= 4400 / 2.2
= 2000
Explanation:
