Ostia are small incurrent pores in the sponge body wall. They allow water to enter the canal system, carrying oxygen and food particles to internal cells. This MCQ belongs to the Porifera topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.
The osculum is the large excurrent opening of a sponge. Water enters through many small ostia, passes through internal chambers, and exits through the osculum. This MCQ belongs to the Porifera topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.
Choanocytes, or collar cells, create water currents and capture suspended food particles in sponges. They are key to sponge feeding because Porifera lack a true digestive tract. This MCQ belongs to the Porifera topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.
Mutualism is a symbiotic relationship in which both partners benefit. Termite gut flagellates help digest cellulose, while the termite provides food and a protected habitat. This MCQ belongs to the Symbiosis topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.
Ciliates commonly possess nuclear dimorphism: a macronucleus controlling metabolic activities and a micronucleus involved in genetic exchange and reproduction. This feature is important in Paramecium. This MCQ belongs to the Ciliates topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.
Correct Answer: A. absence of typical locomotory organelles in adult stage
Explanation:
Many sporozoans, including Plasmodium, lack obvious locomotory organelles in mature stages. They are parasitic protozoans with complex life cycles and specialized stages for invasion and transmission. This MCQ belongs to the Sporozoans topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.
Traditional protozoan classification often used locomotory structures such as pseudopodia, flagella, and cilia. Although modern classification relies more on phylogeny, these features remain useful in practical identification. This MCQ belongs to the Protozoan taxonomy topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.
Phagocytosis is the engulfing of solid food particles by the cell membrane or pseudopodia. In Amoeba, the food becomes enclosed in a food vacuole where digestion occurs. This MCQ belongs to the Protozoan feeding topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.
The contractile vacuole removes excess water entering a freshwater protozoan by osmosis. Without this structure, the cell could swell and burst in hypotonic surroundings. This MCQ belongs to the Protozoan osmoregulation topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.
Paramecium reproduces asexually by transverse binary fission and may exchange genetic material during conjugation. Conjugation increases genetic variation but does not directly increase population number. This MCQ belongs to the Paramecium topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.
Trypanosoma brucei is a flagellated protozoan transmitted by the tsetse fly and causes African sleeping sickness. The parasite lives in blood and tissue fluids and may affect the nervous system. This MCQ belongs to the Trypanosoma topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.
Plasmodium causes malaria and is transmitted by female Anopheles mosquitoes. Its life cycle includes stages in human liver and blood cells as well as sexual stages in the mosquito. This MCQ belongs to the Plasmodium topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.
