Question

Which of the following is the insectivorous plant?
A. Hydrilla
B. Ranunculus
C. Utricularia
D. Castor

Answer 1

Hint: Carnivorous or insectivorous plants are referred to as plants which derive some or most of their nutrients by catching and eating animals or protozoans (insects and other arthropods). Carnivorous plants have been adapted for growing in places where the soil is thin and poor in nutrients- especially nitrogen (e.g. acidic bogs).

Complete answer:
Remember, the Carnivorous plants are mainly found in all continents except Antarctica, and many Pacific islands.
Now let’s discuss all options one by one,
• Hydrilla ( Hydrilla verticillata): is commonly known as water thyme. It is a submersed perennial herb. It is rooted in the bed of the waterbody and consists of long stems (may be 25 feet in length approx.) which branch at the surface where growth becomes horizontal and make dense mats.
• Ranunculus: is a big genus of about 500 species of flowering plants, and has the family Ranunculaceae. Genus members are called as buttercups, spearworts and water.
• Ricinus communis, also called as castor bean or castor oil plant, is believed as a species of perennial flowering plant in the spurge family - Euphorbiaceae (it is the only species in the monotypic genus, Ricinus, and subtribe, Ricinine, crowfoots).
• Utricularia, commonly and collectively known as the bladderworts, is referred to as the genus of carnivorous plants having approximately 233 species. They are found in freshwater and wet soil as terrestrial or aquatic species throughout every continent, except Antarctica. 
So, let’s recap that, Insectivorous plants are referred to as green plants but insectivorous eating habits develop because of deficiency of nitrogen in the soil. They are found to grow in swampy areas like, Nepenthes or pitcher plant, Utricularia or bladderwort. (Remember, it is a hydrophyte insectivorous plant and is used as a pollution indicator).

Therefore, the correct answer is option C.

Additional information:
Many people consume bladderwort to treat urinary tract disorders including kidney stones and urinary tract infections (UTIs), spasms, fluid retention, and swelling. It is also used to stimulate gallbladder secretions as well as to promote weight loss.
Note:
When bladderworts are hungry, they secrete irresistible smells from the sac-like structures which are attached to their underwater mass of roots. Whenever an excited prey comes to investigate the smell, the bladder takes them up and digestion begins. Note that the bladderwort comprises a trap faster than the blink of an eye and uses powerful suction for snatching its prey. The way by which a bladderwort catches its prey is by waiting for prey animals to touch trigger hairs located on the trapdoor that closes the trap watertight.