CBSE 11TH BIOLOGY - Online Test
Q1. Separate xylem and phloem bundles are known as
Answer : Option C
Explaination / Solution:
Separate xylem and phloem bundles are found in dicotyledonous roots. This kind of vascular bundle is called radial vascular bundle.
Q2. A group of plants with similar traits of any rank is
Answer : Option C
Explaination / Solution:
Each category in taxonomic hierarchy represents a rank and is commonly termed as taxon. Hence, the correct option is Taxon.
Q3. Which of the following hormone is used to kill dicotyledonous weeds?
Answer : Option C
Explaination / Solution:
2, 4 D (2,4-Dichlorophenoxyacetic acid)are widely used as herbicides. It is widely used to kill dicotyledonous weeds, does not affect mature monocotyledonous plants.
Q4. In the following two graphs :
i.first graph shows: twitch summation etanus fatigue.
ii. second graph shows: incomplete and complete tetanus.
i.first graph shows: twitch summation etanus fatigue.
ii. second graph shows: incomplete and complete tetanus.
Answer : Option C
Explaination / Solution:
Graph 1 shows muscle fiber tension with time. Which occurs in order as : twitch→summation→tetanus→fatigue.
Graph 2 shows complete and incomplete tetanus. Tetanus is also known as lockjaw, which is a infection characterized by muscle spasm.
Q5. Which one is a heterocrine gland?
Answer : Option A
Explaination / Solution:
Pancreas is called as heterocrine gland because it acts as both endocrine and exocrine gland to secrete hormone as well as digestive enzymes. Testis and Ovary are also heterocrine glands.
Q6. When a fresh water protozoan is placed in marine water
Answer : Option B
Explaination / Solution:
When fresh water protozoan is placed in marine water, the contractile vacuole disappear because the function of vacuole is to expel out excess water but in case of marine water, the water should be retained instead of getting expelled. If the contractile vacuole will not disappear the cell will get dehydrated.
Q7. Rupture and fractionalization of water column present in treachery elements does not occur during ascent of sap due to
Answer : Option A
Explaination / Solution:
Cohesion and adhesion between wall of tracheid and water molecule prevent rupture and fractionalization of water column present in treachery elements during ascent of sap.
Q8. Main role of minor elements is to act as
Answer : Option D
Explaination / Solution:
Micronutrients are required in very small quantity. The main role of micronutrients is to act as cofactor of enzyme. Co-factors increase the efficiency of enzymes.
Q9. Absorption of food takes place in stomach as well as intestine but villi are present in intestine only because :
Answer : Option D
Explaination / Solution:
Villi increases the surface area thereby increasing the absorption of food.The villi also contain lymph vessels for absorbing the products of fat-digestion. From the blood stream, the absorbed food is finally delivered to each and every cell of the body. The mucosal walls of the stomach form irregular folds known as rugae.These help in increasing the surface area to volume ratio of the expanding stomach.
Q10. Find out the mismatched pair :
Answer : Option D
Explaination / Solution:
Different parts of human brain have specializedarea for different receptors. Visual area is located in occipital lobe. General sensory area are located in parietal lobe, smell area is located in frontal area. Speech area is not located in parietal lobe.
