Answer to Question #66544 in Biology for Duaa

Question

Qno1) why is butter solid and mustard oil is liquid at room temperature?
Qno2) why is water an amphoteric molecule?
Qno3) why are enzymes called as biocatalysts?
Qno4) why are echinoderms considered closer to chordates than any other phylums?
Qno5) Give reason why a snail and an octopus are classified under the same phylum?
Qno6) why do the walls of trachea not collapse when there is less air in it?
Qno7) why is a closed circulatory system more efficient than an open circulatory system?

Answer 1

1. Because melting point of butter is higher than that for oil.
2. Because it can act both as an Acid and as an Alkali (H 2 O molecule breaks into H + and OH - ).
3. Because they have biological origin and functionally increase reaction speed.
4. Because the coelom of the animals in this phylum is made of the digestive tube and the endoskeleton is made of 95% of CaCO 3 – just like in Chordates.
5. Presence of 2 paired nerve chords or 3 in bivalves + presence of radula for feeding + presence of the mantle cavity in the dorsal part for respiration and excretion.
6. Because trachea is supported by a series of cartilanginous rings preventing it from collapsing.
7. Because closed circulatory system gives an ability to animals to have control over oxygen exchange. Due to its presence, systemic and pulmonary branches of the system can maintain their respective pressures.