31. Which of the following is the largest group of mammals?
[A] Rodentia
[B] Chiroptera
[C] Carnivora
[D] Insectivora
Show Answer
Correct Answer: A [Rodentia]
Notes:
Rodentia is the largest group of mammals. Rodents are mammals of the rodent order. It is characterized by a pair of continuously moving incisors in each of the upper and lower jaws.
32. Langerhans cells are present in which of the following?
[A] Stratum Spinosum
[B] Stratum Basale
[C] Stratum Granulosum
[D] Stratum Corneum
Show Answer
Correct Answer: A [Stratum Spinosum]
Notes:
Langerhans cells are present in the Stratum Spinosum. Stratum Spinosum has 8-10 layers of many-sided keratinocytes which are closely packed.
33. What is the unit of the Nervous system?
[A] Brain
[B] Spinal Cord
[C] Neuron
[D] Nerves
Show Answer
Correct Answer: C [Neuron]
Notes:
The units that make up the nervous system are nerve cells or neurons. Therefore, it is called the functional and structural unit of the neuron nervous system. Neuron is the largest cell in the body.
34. The open space between bones is filled by which of the following?
[A] air
[B] blood
[C] bone cells
[D] bone marrow
Show Answer
Correct Answer: D [bone marrow]
Notes:
Bone marrow is found in the hollow center of bones. Bone marrow cells – the soft, fatty core of many bones, this protected hollow space makes red blood cells and releases them into the bloodstream.
35. What are some of the common disorders caused by a poor immune system?
[A] Epidemic Diseases
[B] Deficiency diseases
[C] Autoimmune diseases
[D] None of the above
Show Answer
Correct Answer: A [Epidemic Diseases]
Notes:
A disease that affects a large number of people within a community, population, or region is called Epidemic Disease.
36. Why is excretion a vital process in the human body?
- It helps to remove waste products from the body.
- It helps in maintaining the body’s internal environment by regulating chemical composition.
- It aids in the synthesis of crucial biomolecules.
- It generates energy by breaking down food substances.
Select the correct option from the codes given below:
[A] Only 1 & 2
[B] Only 2 & 3
[C] Only 1, 2 & 3
[D] 1, 2, 3 & 4
Show Answer
Correct Answer: A [Only 1 & 2]
Notes:
Excretion is a vital process as it removes waste products from the body and helps in maintaining the body’s internal environment by regulating the chemical composition of blood and other bodily fluids. It does not aid in the synthesis of crucial biomolecules or generate energy by breaking down food substances, which are processes associated with metabolism and digestion, respectively.
37. Which of the following are the main sources of biofertilizers?
[A] bacteria
[B] cyanobacteria
[C] fungi
[D] All of the above
Show Answer
Correct Answer: D [All of the above]
Notes:
Bacteria, cyanobacteria and fungi are the main sources of biofertilizers. These trap atmospheric nitrogen and reduce it to ammonia and make it available to plants. They also convert insoluble phosphates into forms required by plants.
38. Dumb-bell shaped guard cells are present in
____:
[A] Mango
[B] Wheat
[C] Gram
[D] Groundnut
Show Answer
Correct Answer: B [Wheat]
Notes:
Monocost and dicots differ in the location of stomata and shape of guard cells. In monocots stomata are Dumb-bell shaped in dicots they are bean-shaped.
39. Which of the following bacterium causes crown gall disease in plants?
[A] Agrobacterium tumefaciens
[B] Pseudomonas fluorescens
[C] Bacillus thurigiensis
[D] None of the above
Show Answer
Correct Answer: A [Agrobacterium tumefaciens]
Notes:
Crown gall is a disease caused by the bacterium Agrobacterium tumefaciens (synonym Rhizobium radiobacter), which enters the plant through wounds in roots or stems and stimulates the plant tissues to grow in a disorganized way, producing swollen galls. As the disease progresses, plants lose vigour and may eventually die. In science of Biotechnology, it is considered as natural engineer.
40. The largest cells in mammalian blood are ____:
[A] Monocytes
[B] Lymphocytes
[C] Erythrocytes
[D] Basophils
Show Answer
Correct Answer: A [Monocytes]
Notes:
Various components of blood are: Plasma, Erythrocytes (Red Blood Cells), Leucocytes (White Blood Cells) and Thrombocytes/Platelets. Monocytes, also known as macrophages, are the largest blood cells in most mammals, measuring 10-15 cm in diameter. They are leucocytes. Their nuclei are kidney-shaped and cytoplasm is abundant.
