(a) The figure below shows stress-strain curves for two rocks, designated as X and Y. Based on the characteristics of the curves, answer the following questions. Strain (1) What is the mode of failure for Y? 1) What do the regions 'm' and 'n' represent? (1i) What do the points p', 'q and 'r' represent? (6) A sandstone core of 15 cm length and cross-sectional area of 25 cm' was evaluated for permeability, using a constant head permeameter. For a hydraulic head of 5 cm, a total of 100 ml of water was collected in 10 minutes. Estimate hydraulic conductivity (cm/min) using the Darcy's equation, Q = K.A.(dh/dl), where Q= discharge (cm'/min), K = hydraulic conductivity (cm/min), A = cross-sectional area (cm) and (dh/dl) = hydraulic head.