Which of the following statements about DNA is correct?
A. It is usually single-stranded.
B. It contains the sugar ribose.
C. It is located in the nucleus in eukaryotes.
D. Adenine pairs with guanine.
Answer: Option C
Solution (By JKSSB Mock Tests)
DNA is primarily located in the nucleus of eukaryotic cells. It contains deoxyribose (not ribose), is double-stranded, and adenine pairs with thymine. Thus, D is correct.
Explanation:
Autotrophs (self-feeders) include photoautotrophs (plants, algae, cyanobacteria) and chemoautotrophs (some bacteria). They produce organic matter from CO₂. Heterotrophs depend on others, saprotrophs decompose dead matter, parasites live on hosts.
Consider the following statements about the nervous system:
1. The central nervous system consists of the brain and spinal cord.
2. The peripheral nervous system includes cranial and spinal nerves.
3. The autonomic nervous system controls voluntary actions.
Which of the above is/are correct?
Explanation:
Abscisic acid (ABA) is a stress hormone that induces stomatal closure by causing efflux of K⁺ ions from guard cells, leading to loss of turgor, thereby reducing water loss during drought. Auxin and cytokinin promote growth, gibberellin stimulates stem elongation and seed germination. ABA also promotes seed dormancy and leaf senescence.
No comments yet. Be the first to start the discussion!