The individuals in a population can be divided into three age groups: pre-reproductive, reproductive, and post-reproductive age groups. The triangular-shaped graph is observed in developing countries as the pre-reproductive population is more there.
In a growing population of a country, pre-reproductive individuals are more than reproductive individuals.
Whenever the population is of a growing or expanding type, the population of pre-reproductive individuals or the younger population is very large. The reproductive population will be moderate whereas the post-reproductive individuals are very few. Thus, the rate of growth will depend on the size of the pre-reproductive population.
Also Read: Human Population
Match List I with List II.
List I (Interacting species) | List II (Name of interaction) | ||
A | Leopard and a Lion in a forest/grassland | I | Competition |
B | A Cuckoo laying egg in a Crow’s nest | II | Brood parasitism |
C | Fungi and root of a higher plant in Mycorrhizae | III | Mutualism |
D | A cattle egret and a Cattle in a field | IV | Commensalism |
Choose the correct answer from the options given below
Match List I with List II:
List I (Interaction) | List II (Species A and B) | ||
A. | Mutualism | I. | +(A), O(B) |
B. | Commensalism | II. | –(A), O(B) |
C. | Amensalism | III. | +(A), –(B) |
D. | Parasitism | IV | +(A), +(B) |
Choose the correct answer from the options given below:
A bob of heavy mass \(m\) is suspended by a light string of length \(l\). The bob is given a horizontal velocity \(v_0\) as shown in figure. If the string gets slack at some point P making an angle \( \theta \) from the horizontal, the ratio of the speed \(v\) of the bob at point P to its initial speed \(v_0\) is :