Science Group
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Total MCQs
FBISE Biology
Answer: In darkness photosynthesis stops while respiration continues, so the plant releases carbon dioxide.
Answer: Xylem consists of vessels, tracheids, xylem fibres and xylem parenchyma.
Answer: Vessels and tracheids conduct water and give the stem mechanical support.
Answer: Phloem consists of sieve tubes, companion cells, phloem fibres and phloem parenchyma.
Answer: Companion cells keep sieve tubes alive and functional through their nucleus and metabolism.
Answer: Sieve tube cells have no nucleus and rely on companion cells for their functioning.
Answer: The cohesion-tension mechanism sustains a continuous water column that can reach the tops of tall trees.
Answer: Mesophyll cells of the leaves contain most of the chloroplasts where photosynthesis occurs.
Answer: Mesophyll cells are packed with chloroplasts and are the main sites of photosynthesis.
Answer: Plants excrete gases such as carbon dioxide and oxygen and also water, but urea is not a normal plant waste.
Answer: Waste products accumulate in vacuoles and ageing cells, which are later shed by the plant.
Answer: Leaf fall is a way for the plant to dispose of leaves loaded with waste materials.
Answer: Minerals dissolve in soil water and are absorbed through the root hairs.
Answer: Magnesium is at the centre of the chlorophyll molecule and is essential for its formation.
Answer: Nitrogen is an essential component of proteins and nucleic acids in plants.
Answer: Potassium deficiency weakens stems and causes yellowing and scorching of leaf margins.
Answer: Nitrogen is a macronutrient, while iron, zinc and manganese are required only in small amounts.
Answer: Iron is a micronutrient that is needed by plants only in small quantities.
Answer: Iron is needed for chlorophyll formation, so its deficiency causes chlorosis.
Answer: Transpiration helps cool the plant and move water, but it cannot keep plant tissues completely dry.