Which of the following is a correct statement about the human brain?
A. The cerebrum is the centre for balance and coordination.
B. The medulla oblongata regulates heart rate and breathing.
C. The cerebellum controls memory and intelligence.
D. The hypothalamus controls voluntary muscle movements.
Answer: Option B
Solution (By JKSSB Mock Tests)
The medulla oblongata contains vital centers that control involuntary functions like heart rate, breathing, and blood pressure. The cerebrum is responsible for memory, intelligence, and voluntary movements; the cerebellum coordinates balance and movement; the hypothalamus regulates body temperature, hunger, and hormone secretion.
Explanation:
Synapsis (pairing of homologous chromosomes) and crossing over (exchange of genetic material) occur during prophase I of meiosis, not in mitosis. Mitosis involves one division producing two genetically identical diploid daughter cells. Meiosis involves two divisions producing four haploid gametes with genetic variation. Chromosome duplication and sister chromatid separation occur in both. Spindle fibres form in both divisions. Thus, synapsis and crossing over are unique to meiosis.
Explanation:
Vitamin A (retinal) combines with opsin to form rhodopsin in rod cells, necessary for vision in dim light. Deficiency causes night blindness. B₁ is for carbohydrate metabolism, C for collagen, D for calcium.
Explanation:
Syphilis is caused by the spirochete Treponema pallidum and is curable with antibiotics. Hepatitis B and HIV are viral, genital herpes is caused by herpes simplex virus. Gonorrhea and chlamydia are other bacterial STDs. Early diagnosis and treatment prevent serious complications like neurological damage and congenital syphilis.
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