The process of individuals of the same species that have come into the habitat from elsewhere during the time period under consideration is referred as: 
1. Association 
2. Emigration 
3. Competition 
4. Immigration 

What type of human population is represented by the following age pyramid? 

  
1.  Stable population
2.  Declining population
3.  Expanding population
4.  Vanishing population

A country with a high rate of population growth took measures to reduce it. The figure below shows age-sex pyramids of populations. A and B are twenty years apart. Select the correct interpretation about them: 
 
Interpretations

Geometric representation of age structure is a characteristic of:

1. Biotic community

2. Population

3. Landscape

4. Ecosystem