General Science/Everyday Science MCQs
Topic Notes: General Science/Everyday Science
MCQs and preparation resources for competitive exams, covering important concepts, past papers, and detailed explanations.
Plato
- Biography: Ancient Greek philosopher (427–347 BCE), student of Socrates and teacher of Aristotle, founder of the Academy in Athens.
- Important Ideas:
- Theory of Forms
- Philosopher-King
- Ideal State
21
The 'vascular cambium' is a type of:
Answer:
Lateral meristem
Lateral meristems add thickness to woody plants through secondary growth.
22
Which of the following is true of 'sclerenchyma cells'?
Answer:
They have thick secondary walls usually containing lignin
Sclerenchyma cells are specialized for support and are often dead at maturity, leaving behind their rigid cell walls.
23
Which cells in the leaf are specifically arranged to maximize gas exchange?
Answer:
Spongy mesophyll
The spongy mesophyll cells are loosely packed with many air spaces, allowing carbon dioxide to reach the palisade cells efficiently.
24
What is the 'radicle' of an embryo?
Answer:
The embryonic root
The radicle emerges first during germination to establish an anchor and a water source for the plant.
25
In the root, the 'pericycle' is the site where:
Answer:
Lateral roots originate
The pericycle is a layer of cells just inside the endodermis. It remains meristematic and can divide to produce lateral roots.
26
Which plant hormone is commonly known as the 'stress hormone' because it mediates drought responses?
Answer:
Abscisic acid
Abscisic acid (ABA) accumulates in leaves during water stress, causing stomata to close rapidly to conserve water.
27
What is the primary function of 'xylem'?
Answer:
Transporting water and minerals
Xylem tissue consists of tracheids and vessel elements that conduct water and dissolved minerals from the roots to the rest of the plant.
28
The 'epidermis' of a plant often secretes a waxy layer called the:
Answer:
Cuticle
The cuticle is an adaptation to terrestrial life that helps plants minimize water loss from their surfaces.
29
Which tissue is responsible for increasing the diameter of woody stems over time?
Answer:
Lateral meristem
Lateral meristems, which include the vascular cambium and cork cambium, are responsible for secondary growth, which increases the thickness of woody plants.
30
Which of the following is an example of 'negative gravitropism'?
Answer:
Stems growing away from gravity (upward)
Stems grow upward, opposite to the pull of gravity. This ensures that the leaves are positioned to capture sunlight.