IGCSE Biology Paper-4: Specimen Questions with Answers 50 - 51 of 279

Glide to success with Doorsteptutor material for Bank-PO : get questions, notes, tests, video lectures and more- for all subjects of Bank-PO.

Question 50

Edit

Describe in Detail

Essay▾

What do you mean by artificial selection? Is artificial selection affect the natural selection

Explanation

It is modification of a species by man՚s intervention so that certain desirable characteristics are represented in successive generations. Human being through artificial selection has produced several species of dog, pigeons, horse and vegetables. Artificial selection affect the natural selection . Natural selection is based on appearance of variations, competence and adaptations to change in the environment. Artificial selection gives artificial environment to the selected plant and animals and it will eliminate competition adaptation or natural selection.

Passage

The graph shows rate of photosynthesis in different amount of carbon dioxide in the air. By using the graph

Rate of Photosynthesis in Different Amount of Carbon Dioxide

Question 51 (1 of 2 Based on Passage)

Edit

Describe in Detail

Essay▾

What is the relationship between amount of carbon di oxide and the rate of photosynthesis process? What other factors affect the rate of photosynthesis.

Explanation

Carbon dioxide used to make sugar in the photosynthesis reaction. An increase in the concentration of carbon dioxide gives an increase in the rate of photosynthesis. At the fix point rate falls of and at a certain carbon dioxide concentration the rate of photosynthesis stays constant at that time a rise in carbon dioxide levels has no affect on the rate of photosynthesis.

Light and temperature also change the rate of photosynthesis. The rate of photosynthesis increases when light gets brighter. The higher the temperature then the greater the rate of photosynthesis, photosynthesis is a chemical reaction and the rate of most chemical reactions increases with temperature. However, for photosynthesis at temperatures above 40°C the rate slows down.

Developed by: