CBSE 12TH BIOLOGY - Online Test
Q1. Which one of the following acts as a physiological barrier to the entry of microorganisms in human body?
Answer : Option C
Explaination / Solution:
Disease causing microorganism enters through different routes into the body. Physiological barrier prevent their entry. Tears acts as physiological barrier for entry of pathogen.
Q2. In DNA, sugar is attached to nitrogenous base (purine or pyrimidine) through
Answer : Option D
Explaination / Solution:
In DNA, sugar and nitrogenous base are attached with each other through glycosidic bond. Phosphate and next sugar with Phosphodiester linkage and purine and pyrimidine with hydrogen bonds.
Q3. Available organic matter for herbivores is represented by
Answer : Option B
Explaination / Solution:
The organic matter available for herbivores is called net primary productivity (NPP). Total amount of organic matter fix during photosynthesis is called Gross primary productivity (GPP).
Q4. Crosses between two plants by the same variety are called
Answer : Option B
Explaination / Solution:
The crosses between two plants of same varieties is called intravarietal cross. The hybrid obtained from intravarietal cross is more vigorous as they are heterogenic.
Q5. Match the following:
state
a) Tamil Nadu
b) Himachal Pradesh
c) Kerala & Tamil Nadu
d) Uttarakhand
biosphere reserve
i) Nandadevi
ii) Agasthyamalai
iii) cold desert
iv) gulf of Mannar
state
a) Tamil Nadu
b) Himachal Pradesh
c) Kerala & Tamil Nadu
d) Uttarakhand
biosphere reserve
i) Nandadevi
ii) Agasthyamalai
iii) cold desert
iv) gulf of Mannar
Answer : Option C
Explaination / Solution:
- In 1986, a group of 21 islets lying off the Tamil Nadu coast between Thoothukudi and Dhanushkodi was declared the Gulf of Mannar Marine National Park. The park and its 10 km buffer zone were declared a Biosphere Reserve in 1989.
- Cold Desert Biosphere Reserve is a biosphere reserve located in the western Himalayas region, within Himachal Pradesh state in North India.
- The Agasthyamalai Biosphere Reserve was Established in 2001 and includes 3,500.36 km² of which 1828 km² is in Kerala and 1672.36 km² is in Tamil Nadu.
- The Nanda Devi National Park, established in 1982, is a national park situated around the peak of Nanda Devi in the state of Uttarakhand in northern India.
Q6. The glandular tissue of each breast is divided into 15-20
Answer : Option C
Explaination / Solution:
The glandular tissue of each breast is divided into 15-20 mammary lobes which contain cluster of alveoli. Cells of alveoli secretes milk.
Q7. In T. H. Morgan"s Experiment on Drosophilia what will be the result when F1 female flies are crossed with double recessive male files?
Answer : Option A
Explaination / Solution:
When F1 female flies (Drosophila) obtained in crossed with double recessive male flies 83% parental combination are obtained along with 17% recombinant offspring are formed.
Q8. Spirulina is a
Answer : Option C
Explaination / Solution:
Spirulina is an Algae found in water. It is unicellular and rich in proteins. It is used as single cell protein as substitute of plant or animal protein.
Q9. Water bodies and aquatic flora will be badly affected by :
Answer : Option D
Explaination / Solution:
Acid rain is the rainwater that contain Sulphuric acid and Nitric acid. These acids make the water bodies acidic by changing pH. At higher pH aquatic organisms are badly affected.
Q10. Identify “A” and “B” in the T.S of mature anther
Answer : Option D
Explaination / Solution:
The mature anther consists of four microsporangia which contain four layers. The inner most layer is called tapetum that provide nutrient to growing microspores and tissues inside it are called microspore mother cell that produce pollen grain.
