The adjustable ring of contractile and connective tissues that controls the amount of light entering the eye is the ____.

A. lens
B. cornea
C. pupil
D. iris
E. retina


Answer: D

Biology & Microbiology

You might also like to view...

True or false: Freshwater flatworms and earthworms are similar in that their excretory systems reabsorb electrolytes and eliminate concentrated urine

A. true B. false

Biology & Microbiology

A group of plant geneticists discovers a mutant plant that has a deficiency in gibberellin production

All other hormones, including auxins, cytokinins, florigens, ethylene, and abscisic acid, are produced in normal quantities and are not directly affected by this mutation. Based on this scenario, the mutant plant most likely exhibits A) stomata that don't close. B) a lack of gravitropism in the roots. C) a lack of phototropism in the shoots. D) a dwarf growth pattern (very short stem). E) delayed senescence.

Biology & Microbiology

Bacteriophages replicate in

a. a yeast cell b. bacterial cells c. human cells d. a large virus

Biology & Microbiology

What is the major function of the colon?

A. to churn food B. to form feces C. to digest/absorb D. to eliminate iron E. to serve as a passageway only

Biology & Microbiology