Consider statements about human diseases: 1. Typhoid is caused by a bacterium. 2. Malaria is caused by a protozoan. 3. Dengue is caused by a virus. Which are correct? MCQ with Answer and Explanation
Consider statements about human diseases: 1. Typhoid is caused by a bacterium. 2. Malaria is caused by a protozoan. 3. Dengue is caused by a virus. Which are correct?
A. 1 and 2 only
B. 2 and 3 only
C. 1 and 3 only
D. 1, 2 and 3
Answer: Option D
Solution (By JKSSB Mock Tests)
Typhoid fever is a systemic bacterial infection caused by Salmonella enterica serotype Typhi, transmitted through contaminated food and water. Malaria is a life-threatening disease caused by protozoan parasites of the genus Plasmodium (like P. falciparum), transmitted by Anopheles mosquitoes. Dengue fever is a viral infection caused by the Dengue virus (a flavivirus), transmitted by Aedes mosquitoes. All three statements correctly identify the causative agents of these major diseases.
Consider the following statements about the human heart:
1. The right atrium receives blood from the vena cavae.
2. The left ventricle pumps blood to the lungs.
3. The septum separates the left and right sides.
Which of the above is/are correct?
Explanation:
The right atrium receives deoxygenated blood; the left ventricle pumps to the body (not lungs). Septum divides the heart. So 2 is incorrect.
Explanation:
The Casparian strip is a waterproof band of suberin and lignin found in the radial and transverse cell walls of the endodermis (the innermost layer of the cortex) in plant roots. It acts as a barrier to the passive flow of water and dissolved minerals through the cell walls (the apoplastic pathway). This forces water and solutes to cross the selectively permeable plasma membrane and enter the symplastic pathway, allowing the plant to control and filter what enters the vascular cylinder (stele).
Explanation:
Under normal conditions, the brain relies almost exclusively on glucose for energy. During prolonged fasting, it can adapt to use ketone bodies. Fatty acids cannot cross the blood-brain barrier.
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