CBSE 12TH BIOLOGY - Online Test
Q1. The more fundamental type of ecological pyramid showing the quantitative relationships of the standing crops will be
Answer : Option C
Explaination / Solution:
The pyramid of biomass is more fundamental, they represent the quantitative relationships of the standing crops.
In this pyramid there is a gradual decrease in the biomass from the producers to the higher trophic levels. The biomass here the net organisms collected from each feeding level and are then dried and weighed.
This dry weight is the biomass and it represents the amount of energy available in the form of organic matter of the organisms. In this pyramid the net dry weight is plotted to that of the producers, herbivores, carnivores, etc. More the number of crop plants higher the biomass.
Q2. "Jaya" and "Ratna" developed for green revolution in India are the varieties of
Answer : Option D
Explaination / Solution:
Jaya and Ratna are varieties of maize developed by Indian council of agricultural research. These varieties are high yielding and resistance to disease.
Q3. Endemics of western Ghats include
Answer : Option C
Explaination / Solution:
Endemism is the ecological state of a species being unique to a defined geographic location, such as an island, nation, country or other defined zone, or habitat type.
Notable endemics are the Nilgiri leaf monkey and the brown and carmine Beddome's toad of the Western Ghats.
Q4. Testes are located outside the abdominal cavity in scrotum because
Answer : Option D
Explaination / Solution:
The testes are located outside the abdominal cavity in a pouch called scrotum. The scrotum helps in maintaining the low temperature of testes necessary for spermatogenesis.
Q5. A cross between AaBB X aaBB yields a genotypic ratio of
Answer : Option D
Explaination / Solution:
Genotypic ratio of cross between AaBB and aaBB will be 1:1 as AaBB and aaBB in F1 generation.
Q6. A sewage treatment process in which a part of decomposer bacteria present in the wastes is recycled into the starting of the process is called
Answer : Option A
Explaination / Solution:
Activated sludge treatment is a step in sewage treatment in which a part of decomposer bacteria present in wastes is recycled into the starting of treatment to maintain bacteria.
Q7. Effects of thermal pollution of water include :
a) increased BOD
b) increased toxicity of discharged chemicals
c) decreased microbial activity
a) increased BOD
b) increased toxicity of discharged chemicals
c) decreased microbial activity
Answer : Option D
Explaination / Solution:
An effect of thermal pollution of water includes increased Biological Oxygen Demand (BOD) and decreased microbial activity. Some organisms are able to survive only at normal temperature.
Q8. Filiform apparatus present at micropylar part of the Synergids help in
Answer : Option A
Explaination / Solution:
Filiform apparatus is finger-like projection attached with egg apparatus. This apparatus guide the pollen tube carrying male gametes for facilitating Syngamy.
Q9. The polyacrylamide gel is used to separate proteins as
Answer : Option B
Explaination / Solution:
Protein molecules are smaller than DNA polynucleotide. Protein and DNA can be separated by polyacrylamide gel having minute pores through which protein can pass but not the DNA.
Q10. An important evidence in favour of organic evolution is the occurrence of
Answer : Option D
Explaination / Solution:
There are many evidences that favor the organic evolution of life. According to this concept life originate from pre-existing organisms by evolution in cousr of time. Homologous and vestigial organs hit the uses of different organs in different organism for different purpose.
