Consider statements about evolution: 1. Genetic drift is a random change in allele frequencies. 2. Gene flow occurs through migration. 3. Natural selection is a random process. Which are correct? MCQ with Answer and Explanation
Consider statements about evolution: 1. Genetic drift is a random change in allele frequencies. 2. Gene flow occurs through migration. 3. Natural selection is a random process. Which are correct?
A. 2 and 3 only
B. 1, 2 and 3
C. 1 and 3 only
D. 1 and 2 only
Answer: Option D
Solution (By JKSSB Mock Tests)
Genetic drift is the random fluctuation of allele frequencies in a population, particularly significant in small populations, due to chance events. Gene flow (migration) is the transfer of alleles from one population to another through the movement of individuals or gametes. Natural selection is a non-random, deterministic process where individuals with traits better suited to their environment have higher survival and reproductive success. Thus, statements 1 and 2 are correct.
Explanation:
The pancreas functions as an exocrine gland (secreting digestive enzymes into the duodenum via the pancreatic duct) and an endocrine gland (secreting insulin, glucagon, somatostatin from the islets of Langerhans into the blood). Thyroid, pituitary, and adrenals are purely endocrine.
Explanation:
Transcription, catalyzed by RNA polymerase, copies the genetic information from a DNA template into a complementary mRNA strand. Translation is protein synthesis.
Explanation:
The epiglottis is a cartilaginous flap that covers the glottis (the opening into the larynx and trachea) during swallowing, directing food and liquid into the esophagus. The tongue moves food, the glottis is the opening itself, and the uvula is a soft tissue hanging at the back of the palate that assists in speech and prevents nasal regurgitation.
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