Which of the following is a characteristic feature of the phylum Porifera?
A. Jointed appendages
B. Nematocysts
C. Radial symmetry
D. Water canal system
Answer: Option D
Solution (By JKSSB Mock Tests)
Porifera (sponges) are characterized by the presence of a complex water canal system (canal system) used for food gathering, respiratory exchange, and waste removal. Water enters through numerous small pores called ostia and exits through a large opening called the osculum. They are mostly marine and asymmetrical.
Explanation:
The aorta is the main and largest artery originating from the left ventricle, distributing oxygenated blood to all parts of the body through its branches. The pulmonary artery carries deoxygenated blood to lungs. Coronary arteries supply the heart muscle, carotid arteries supply the brain. The aorta has a diameter of about 2-3 cm in adults.
Explanation:
Streptococcus thermophilus and Lactobacillus bulgaricus are used as starter cultures in yogurt production. They ferment lactose to lactic acid, causing milk proteins to coagulate, giving yogurt its thick texture and tangy taste. Bacillus cereus causes food poisoning, E. coli can be pathogenic, Salmonella causes typhoid.
Explanation:
Certain bacteria, like Bacillus megaterium and Alcaligenes eutrophus, accumulate polyhydroxyalkanoates (PHA) such as PHB as intracellular carbon and energy storage under nutrient stress. These are used to make biodegradable plastics. E. coli is engineered for some bioplastics, but natural producers include Bacillus.
No comments yet. Be the first to start the discussion!