A chemical, which kills the weeds, is known as:

Related Mcqs:

1. An animal which captures and readily kills live animals for its food is known as:

   A. Predator
   B. Parasite
   C. Symbionts
   D. None of these

2. The removal of weeds by ploughing is called:

   A. Mulching
   B. Fallowing
   C. Tilling
   D. Contour farming

3. Sewage drained into water bodies kills fishes because:

   A. It gives off a bad small
   B. It removes the food eaten by fishes
   C. It increases the competition with fishes for dissolved oxygen
   D. Excessive CO2 is added to water

4. The back and forth movements of chemical elements, between organisms and environment along characteristic circular paths and known as:

   A. Biochemical cycles
   B. Ecological cycles
   C. Chemical cycles
   D. None of these

5. The rate at which light energy is converted into chemical energy of organic molecules is the ecosystem’s:

   A. Net primary productivity
   B. Gross secondary productivity
   C. Net secondary productivity
   D. Gross primary productivity

6. The chemical produced by the host plant to protect themselves against fungal infection is:

   A. Toxin
   B. Hormone
   C. Phytotoxin
   D. Phytoalexin

7. By chemical composition the humus has maximum percentage of:

   A. Nitrogen
   B. Oxygen
   C. Carbon
   D. Hydrogen

8. The processes involved in the chemical weathering are:

   A. Carbonation and oxidation
   B. Hydrolysis and chelation
   C. Hydrolysis and reduction
   D. All of these

9. A pollutant is any substance, chemical cycles

   A. The natural geo-chemical cycles
   B. The natural balance of our environment
   C. The natural flora of a place
   D. The natural wildlife of a region

10. The bacteria, which reduce nitrates in the soil to gaseous nitrogen, are known as denitrifying bacteria such as:

    A. Nitromonas
    B. Pseudomonas
    C. Nostoc
    D. Rhizobium