Which of the statements given below is not true
about formation of Annual Rings in trees?
AI-generated explanation. Check against your textbook.
Explanation:
Annual rings are formed due to seasonal variation in wood, with spring wood (light, spacious vessels) and autumn wood (darker, dense vessels) produced within one year. The cambium’s differential activity creates these light and dark bands. In temperate regions, distinct rings are visible because seasons differ markedly; in tropical regions, rings may be faint or absent due to less pronounced seasonality. Statement 3 says rings are not prominent in temperate region, which is not true. Therefore option 3 is the incorrect statement.
? Did You Know?
In NCERT books, annual rings are used to estimate the age of a tree and study past climatic conditions.
? NCERT Memory Line:
Annual rings result from cambial activity varying with seasons; they are prominent in temperate regions where seasons differ.
The concept of "Omnis cellula-e cellula" regarding
cell division was first proposed by:
AI-generated explanation. Check against your textbook.
Explanation:
The correct option is 3, Rudolf Virchow. He stated the concept “omnis cellula e cellula,” meaning every cell arises from pre-existing cells, adding to the cell theory. NCERT credits Schleiden and Schwann with the idea that cells are fundamental units of life, while Virchow added that new cells come from existing ones. Aristotle is not part of the modern cell theory and suggested spontaneous generation, which is not accepted in NCERT biology. Therefore, the phrase “omnis cellula e cellula” is attributed to Virchow and explains how cell division occurs in living organisms.
🧠 Did You Know?
Virchow’s addition completed the cell theory by emphasizing the origin of new cells from old cells during division.
💡 NCERT Memory Line:
Omnis cellula e cellula — every cell arises from pre-existing cells (Virchow).
Consider the following statements:
(A) Coenzyme or metal ion that is tightly bound to
enzyme protein is called prosthetic group.
(B) A complete catalytic active enzyme with its
bound prosthetic group is called apoenzyme.
Select the correct option.