Which one of the following organisms bears hollow
and pneumatic long bones?
AI-generated explanation. Check against your textbook.
Explanation:
Option 1, Neophron, is a bird. Birds have hollow and pneumatic long bones that are connected to air sacs, making the bones light for flight. This feature is described in NCERT biology when explaining the skeletal system of birds. The other options are non-bird animals: Hemidactylus is a reptile (gecko); Macropus is a mammal (kangaroo); Ornithorhynchus is a monotreme mammal (platypus). Their bones are not hollow and pneumatic like birds’ bones.
🧠 Did You Know?
Bird bones are often filled with air spaces that reduce weight without sacrificing strength, aiding flight.
💡 NCERT Memory Line:
Birds possess hollow, pneumatic long bones connected to air sacs, aiding flight and reducing weight.
Read the following statements.
A. Metagenesis is observed in Helminths.
B. Echinoderms are triploblastic and coelomate
animals.
C. Round worms have organ-system level of body
organization.
D. Comb plates present in ctenophores help in
digestion.
E. Water vascular system is characteristic of
Echinoderms.
Choose the correct answer from the options given
below.
AI-generated explanation. Check against your textbook.
Explanation:
The correct statements are B, C and E. Echinoderms are triploblastic and coelomate (true). Roundworms (Nematoda) have organ-system level organization (true). Echinoderms possess a water vascular system (true).
🧠 Did You Know?
Metagenesis (alternation of generations) is typical in some cnidarians and may be mentioned in NCERT with examples like Obelia, not in Helminths. Comb plates in ctenophores are for locomotion, not digestion.
💡 NCERT Memory Line:
NCERT states that Echinoderms are triploblastic, coelomate; nematodes show organ-system level organization; and water vascular system is a hallmark of Echinoderms. It also notes that comb plates aid movement in ctenophores, while digestion occurs in the gastrovascular system.
Which of the following characteristics is incorrect
with respect to cockroach?
AI-generated explanation. Check against your textbook.
Explanation:
The incorrect statement is option 1. In cockroaches, gastric caeca are present at the junction of foregut and midgut, not at the junction of midgut and hindgut. Thus, the described location “junction of midgut and hind gut” is wrong according to NCERT.
🧠 Did You Know?
Hypopharynx is a tongue-like structure located within the mouth cavity (the cavity enclosed by the mouthparts) and helps in manipulating food.
💡 NCERT Memory Line:
In female cockroach, the genital pouch is formed by specific sternites (generally described in NCERT as formed by the 7th–9th sternites in some texts), assisting in reproductive anatomy.
The fruit fly has 8 chromosomes (2n) in each cell.
During interphase of Mitosis if the number of
chromosomes at G1 phase is 8, what would be the number of chromosomes after S phase?