This question was well attempted by the candidates. In
1(a), majority of the candidates were able to identify specimens D(Pebbles or sandstone), E(Granite) and F(Marble). However, in
1(b-c) most of the candidates could neither classify specimens D(Pebbles or sandstone), E(Granite) and F(Marble) according to their mode of formation nor state the characteristics of each of specimens D(Pebbles or sandstone) and E(Granite). Although, in
1(d), majority of the candidates were able to state the ways in which specimen E(Granite) is economically important.
The expected answers include:
(b) Classification of Specimens D, E and F according to their mode of formation
Specimens
D - Sedimentary rock
E - Igneous rock
F - Metamorphic rock
(c) Characteristics of specimens D and E.
Specimen D (Pebbles/Sandstone)
- Occurs in layers or strata
- May be coarse, fine, soft or hard
- Non-crystalline in nature
- May contain fossils/plant and animal remains
- Not resistant to erosion
- May be porous
SpecimenE(Granite)
- Crystalline in nature/contain crystals
- It is massive
- Very hard
- Impermeable to water
- Highly resistant to erosion and weather element
- Does not contain fossils