In the taxonomic categories which hierarchical arrangement in ascending order is correct in case of
animals?
AI-generated explanation. Check against your textbook.
Explanation:
The correct ascending order in taxonomy is: Kingdom, Phylum, Class, Order, Family, Genus, Species. This sequence is the standard hierarchical arrangement described in NCERT biology for animals. Each level becomes more specific from broad grouping (Kingdom) to the most specific (Species).
π§ Did You Know?
Each level shares common characteristics; for example, organisms in the same phylum share fundamental body plans, while those in the same species can usually interbreed.
π‘ NCERT Memory Line:
King Philip Came Over For Good Soup (Kingdom, Phylum, Class, Order, Family, Genus, Species).
In which of the following animals, digestive tract has additional chambers like crop and gizzard?
AI-generated explanation. Check against your textbook.
Explanation:
Digestive tract with crop and gizzard is found in birds. In option 4, Pavo (peafowl), Psittacula (parakeet), and Corvus (crow) are birds that have a crop for storage and a gizzard (ventriculus) for grinding food. NCERT explains these as features of the avian digestive system.
π§ Did You Know?
Birds often swallow grit to help the gizzard grind food since they lack teeth.
π‘ NCERT Memory Line:
Birds have a crop and a gizzard as parts of their specialized digestive system.
Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): All vertebrates are chordates but all chordates are not vertebrates. Reason (R): Notochord is replaced by vertebral column in the adult vertebrates.
In the light of the above statements, choose the most appropriate answer from the option given below :
AI-generated explanation. Check against your textbook.
Explanation:
Statement A is true: every vertebrate is a chordate, but not every chordate is a vertebrate. Statement R is true: in vertebrates, the notochord is replaced by the vertebral column during development. However, R does not explain why vertebrates are chordates; it explains a developmental change within vertebrates. Therefore, both are correct, but R is not the direct explanation of A. The correct option is 2.
π§ Did You Know?
In many vertebrates, the notochord is replaced by the vertebral column, but remnants may persist as intervertebral discs.
π‘ NCERT Memory Line:
βAll vertebrates are chordates, but all chordates are not vertebrates. In vertebrates, the notochord is replaced by the vertebral column.β
AI-generated explanation. Check against your textbook.
Explanation:
Tegmina are the thickened, protective forewings of cockroaches and other insects. They arise from the mesothorax (the second thoracic segment). Thus, option 2 is correct. The hindwings, when present, develop from the metathorax and are usually folded under the tegmina.
π§ Did You Know?
In cockroaches, the forewings (tegmina) act as protective covers for the delicate hindwings and abdomen when at rest.
π‘ NCERT Memory Line:
The forewings are the tegmina and are derived from the mesothorax, while hindwings come from the metathorax.
Given below are two statements: Statement I: Mycoplasma can pass through less than 1 micron filter size. Statement II: Mycoplasma are bacteria with cell wall.
In the light of the above statements, choose the most appropriate answer from the options given below
AI-generated explanation. Check against your textbook.
Explanation:
Statement I is correct: Mycoplasma are very small bacteria that can pass through filters with pore sizes less than 1 micron (e.g., 0.45 ΞΌm). Their lack of a cell wall contributes to their flexible shape and small size. Statement II is incorrect: Mycoplasma do not have a cell wall; NCERT states they are the smallest bacteria that lack a cell wall. Therefore, the correct choice is: Statement I is correct but Statement II is incorrect.
π§ Did You Know?
Because they lack cell walls, Mycoplasma are resistant to many antibiotics that target cell wall synthesis (like penicillin), and they have variable shapes due to their membrane-rich structure.
π‘ NCERT Memory Line:
Mycoplasma are the smallest bacteria that lack cell walls.
Select the incorrect statement with reference to mitosis:
AI-generated explanation. Check against your textbook.
Explanation:
Option 2 is incorrect. In mitosis, spindle fibers attach to kinetochores, which are protein structures at the centromere region of each chromosome. The attachment is to the kinetochore, not directly to the centromere as a general area. The NCERT description emphasizes kinetochores at the centromere for spindle attachment. The other statements are correct: during metaphase chromosomes align at the equator (1); during anaphase sister chromatids separate at the centromeres and move to opposite poles (4); and chromosomes decondense during telophase (3).
π§ Did You Know?
Kinetochores are protein structures assembled at the centromere; spindle fibers connect to them to pull chromatids apart.
π‘ NCERT Memory Line:
βSpindle fibers attach to kinetochores at the centromere to separate chromatids during mitosis.β