Assertion (A): In humans, filariasis is characterized by inflammation in the lower limbs.
Reason (R): Filarial worm usually lives in the lymphatic vessels of the lower limbs.
Reason (R): Filarial worm usually lives in the lymphatic vessels of the lower limbs.
Show Hint
- Both (A) and (R) are true and (R) is the correct explanation of (A).
- Both (A) and (R) are true, but (R) is not the correct explanation of (A).
- (A) is true, but (R) is false.
- (A) is false, but (R) is true.
The Correct Option is A
Solution and Explanation
Top Questions on human health and disease
Student to attempt either option (A) or (B):
(A) Give an account of the generalised structure of an antibody molecule produced by B-lymphocytes in response to the pathogen.
OR
(B) Other than public awareness and counselling, enlist four measures taken up by NACO, WHO and other NGOs to prevent the spread of HIV infection in the society.- CBSE CLASS XII - 2025
- Biology
- human health and disease
Read the following passage and answer the questions that follow. Prevention is the frontline response to drug use. Effective interventions address the underlying conditions contributing to drug use, such as a lack of connection to family or community, instability, insecurity, trauma, mental health issues, etc. When addressed, these factors can effectively prevent the initiation of drug use and the progression to drug use disorders. Study the few key figures of drug use given below and answer the questions that follow.
(a) What do you infer from the figures in Table No. 1 about the people with drug use disorders, 2022 (in million)? State any two of your observations.
(b) How are Hepatitis C and HIV related to drug use disorders by people, as shown in Table No. 2? State the correlation between the two.
(c)
- [(i)] Give the scientific name of (p) shown in Table No. 1.
OR - [(ii)] Give the scientific name of (q) shown in Table No. 1.
- CBSE CLASS XII - 2025
- Biology
- human health and disease
- [(i)] Give the scientific name of (p) shown in Table No. 1.
- A characteristic property that distinguishes a malignant tumor from a benign tumor is:
- CBSE CLASS XII - 2025
- Biology
- human health and disease
Immunity in our body is of two types: (i) Innate immunity and (ii) acquired immunity. Innate immunity is a non-specific defence mechanism, whereas acquired immunity is pathogen-specific; it is called specific immunity too. Acquired immunity is characterised by memory. Antibodies are specific to antigens and there are different types of antibodies produced in our body: they are IgA, IgE, IgG and IgM. It shows primary response when it encounters the pathogen for the first time and secondary response during the subsequent encounters with the same Antigen/Pathogen.
(a) Name the two types of specialised cells which carry out the primary and secondary immune response.
(b) Why is the antibody-mediated immunity also called as humoral immune response?
Attempt either sub-part (c) or (d):
(c) The organ transplants are often rejected if taken from suitable compatible persons.
(i) Mention the characteristic of our immune system that is responsible for the graft rejection.
(ii) Name the type of immune response and the cell involved in it.
OR
(d) How is active immunity different from passive immunity?- CBSE CLASS XII - 2025
- Biology
- human health and disease
- Samples of blood and urine of a sportsperson are collected before any sports event for drug tests.
(a) Why there is a need to conduct such tests?
(b) Name the drugs the authorities usually look for.
(c) Write the generic names of two plants from which these drugs are obtained.
- CBSE CLASS XII - 2025
- Biology
- human health and disease
Questions Asked in CBSE CLASS XII exam
- A coil of 60 turns and area \( 1.5 \times 10^{-3} \, \text{m}^2 \) carrying a current of 2 A lies in a vertical plane. It experiences a torque of 0.12 Nm when placed in a uniform horizontal magnetic field. The torque acting on the coil changes to 0.05 Nm after the coil is rotated about its diameter by 90°. Find the magnitude of the magnetic field.
- CBSE CLASS XII - 2025
- Magnetism and matter
- If \( x = e^{\frac{x}{y}} \), then prove that \( \frac{dy}{dx} = \frac{x - y}{x \log x} \).
- CBSE CLASS XII - 2025
- Differentiation
- Nandita and Prabha were partners in a firm. Nandita withdrew Rs 3,00,000 during the year for personal use. The partnership deed provides for charging interest on drawings @ 10\% p.a. Interest on Nandita's drawings for the year ended 31st March, 2024 will be :
- CBSE CLASS XII - 2025
- Partnership Accounts
Answer the following questions:
- [(i)] Describe the population growth curve applicable in a population of any species in nature that has unlimited resources at its disposal.
- [(ii)] Explain the equation of this growth curve.
- [(iii)] Name the growth curve and depict a graphical plot for this type of population growth.
- [(i)] Explain the conclusion drawn by Alexander von Humboldt during his extensive explorations in the wilderness of South American jungles.
- [(ii)] Give the equation of the Species-Area relationship.
- [(iii)] Draw a graphical representation of the relation between species richness and area for a wide variety of taxa such as birds, bats, etc.
- CBSE CLASS XII - 2025
- Organisms and Populations
Student to attempt either option (A) or (B):
(A) Explain how the interaction between a fig tree and its tight one-to-one relationship with the pollinator species of wasp is one of the best examples of mutualism.
OR
(B) Correctly depict (also indicate the trophic level) and describe the ecological pyramid of number with 32 birds dependent on 20 insects feeding on one banyan tree.- CBSE CLASS XII - 2025
- Organisms and Populations