The ultimate source of energy for all ecosystems is: MCQ with Answer and Explanation

The ultimate source of energy for all ecosystems is:
A. Geothermal heat
B. Wind
C. Water
D. Sun
Answer: Option D
Solution (By JKSSB Mock Tests)
Solar energy is captured by photosynthetic autotrophs and converted to chemical energy, which then flows through food chains. Except for deep-sea hydrothermal vents relying on chemosynthesis, the sun powers virtually all life on Earth.

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Practice More Biology Questions

Question #1
The glomerular filtration rate (GFR) in a healthy adult is approximately:
A. 250 mL/min
B. 125 mL/min
C. 500 mL/min
D. 50 mL/min

Correct Answer: Option B


Explanation:
Glomerular filtration rate (GFR) is the volume of filtrate formed per minute by both kidneys, normally about 125 mL/min (180 L/day). Nearly 99% of the filtrate is reabsorbed, leaving about 1-2 liters of urine per day. GFR is regulated by the juxtaglomerular apparatus. It's an important clinical indicator of kidney function, estimated from serum creatinine.

This question belongs to: Science Biology
Question #2
In the male reproductive system, the spermatozoa are stored and mature in the:
A. Prostate gland
B. Seminal vesicles
C. Epididymis
D. Vas deferens

Correct Answer: Option C


Explanation:
The epididymis is a coiled tube on the posterior surface of the testis where spermatozoa undergo maturation and are stored until ejaculation. Sperm acquire motility here. Seminal vesicles and prostate gland secrete seminal fluid. Vas deferens transports sperm from epididymis to ejaculatory duct. Testes produce sperm and testosterone. Sperm maturation includes gaining ability to fertilize.

This question belongs to: Science Biology
Question #3
In genetic code, how many codons code for the amino acid tryptophan?
A. 6
B. 4
C. 1
D. 2

Correct Answer: Option C


Explanation:
Tryptophan is encoded by a single codon, UGG. Methionine (AUG) is also encoded by a single codon. The other amino acids have multiple codons (degeneracy). For example, leucine has 6 codons. The single codons for Trp and Met are significant as they are less likely to tolerate mutations.

This question belongs to: Science Biology