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Q71. In an outcrop we find that the bedding planes are vertical and cleavage surfaces are horizontal. Which of the following fold types is/are inferred from this observation?
The correct answer is Recumbent fold, Neutral fold. In a folded rock, the 'cleavage' acts like an imaginary wall cutting straight down the middle of the fold (the axial plane). If the cleavage is perfectly horizontal (flat on the ground), the fold is lying down on its side. This type of sideways fold is explicitly called a 'Recumbent fold'. A 'Neutral fold' closes sideways rather than up or down, which also fits this horizontal-axis geometry. Upright and vertical folds stand straight up.
Q72. Which of the following statements is/are NOT correct?
The correct answer is (111) lies in zone . In crystallography, a face belongs to a 'zone' if it is perfectly parallel to the zone's axis. There is a simple math rule (Weiss zone law) to check this: multiply the face numbers by the zone numbers, and if they add up to zero, it is correct. For option D, (1*1) + (1*1) + (1*1) equals 3, not zero. Therefore, face (111) does NOT lie in zone , making it the only incorrect statement.
Q73. Choose the correct combination(s) of type of dentition of Bivalvia and the corresponding representative genus.
The correct answer is Taxodont - Nucula, Isodont - Spondylus, Pachydont - Hippurites, Desmodont - Mya. Bivalves (clams) have tiny teeth on their hinges to lock their shells together. In paleontology, these are standard textbook pairings: Nucula has many tiny identical teeth (Taxodont), Spondylus has symmetrical curved teeth (Isodont), Hippurites has massive, thick, uneven teeth (Pachydont), and Mya has spoon-like spongy teeth (Desmodont). All the pairings listed are scientifically accurate.
Q74. Choose the landform(s) resulting from glacial erosion.
The correct answer is Fjords, Cirques. Glaciers act like giant bulldozers, gouging and scraping the earth (erosion). A 'Fjord' is a massive, deep valley carved out by ice. A 'Cirque' is a bowl-shaped hollow scooped out of a mountain top. Conversely, 'Moraines' and 'Drumlins' are piles of dirt and rocks that the glacier dumped and left behind (deposition), so they are not erosional landforms.