Explanation

(a) Osmosis is the process by which water molecules or solvent move from area or region of weaker solution through a semi-permeable membrane. It can also be defined as the movement of water or water molecules from a region of higher concentration of water molecules to a region of weaker concentration of water molecules through a semi-permeable membrane.

(b)

• A young herbaceous plant, balsom or water plant, is uprooted.
• The roots are washed with water to remove the soil particles.
• Expose the set-up to sunlight and allow it to stand for about one to six hours.
• Remove the plant and wash the roots thoroughly and make transverse sections of the root, stem and leaf.
• Then, observe the sections under the microscope or hand lens.
• It will be observed that only the xylem tissue picks the colour of the dye and will be stained red, indicating that water moves through xylem tissues.

(c)(i) When a red blood cell is placed in hypotonic or weaker solution, water enters the red blood cell by osmosis through the cell membrane which serves as a semi-permeable membrane. Continuous gain or absorption of water by the red blood cell makes the cell swell or enlarge in size and eventually burst. Hence hemolyses or heamolysis takes place.

(b (ii) Three conditions that may cause heamolysis are:

(1) disease attack

(2) abuse or use of drugs and food

(3) poisoning

(4) infection/ epidemic

(5) industrial activities/ pollution.

Correct Answer: C. gametophyte

Correct Answer: A. some towns contain features of rural living

Correct Answer: a) Hair

Correct Answer: C. extractive occupation

Explanation

p*e = e*p = p

p + e - \(\frac{pe}{2}\) = p

e - \(\frac{pe}{2}\) = 0

e(\(1 - \frac{p}{2}\)) = 0

e = 0

p*p\(^{-1}\) = e

p - p\(^{-1}\) - \(\frac{pp^{-1}}{2}\) = 0

p\(^{-1}\) - \(\frac{pp}{2}\) = -p

p\(^{-1}\) (1 - \(\frac{p}{2}\)) = -p

p\(^{-1}\) = \(\frac{-p}{1 - \frac{p}{2}}\)

Inverse of -1 \(\to\) p = -1

p\(^{-1}\) = \(\frac{-1}{1 - (\frac{-1}{2})} = \frac{-1}{\frac{3}{2}}\)

= \(\frac{-2}{3}\)

(b) m*7 = m + 7 - \(\frac{7m}{2}\), m*5 = m + 5 - \(\frac{5m}{2}\)

m*7 = m*5, m + 7 - \(\frac{7m}{2}\) = m + 5 - \(\frac{5m}{2}\)

7 - 5 = -\(\frac{5m}{2} + \frac{7m}{2}\)

2 = \(\frac{2m}{2}\)

m = 2

Correct Answer: C. Monopolistic firm

Explanation

Monopolistic firm is characterizes by an industry in which many firms offer products or services that are similar, but not perfect substitutes. Barriers to entry and exit in a monopolistic competitive industry are low, and the decisions of any one firm do not directly affect those of its competitors.

Correct Answer: D. negative

Correct Answer: A. 26

Explanation

n(P \(\cup\) Q) = m(P \(\cap\) C)

38 = 19 = n(C) - 7

n(C) = 38 - 12

= 26

Correct Answer: D. Savanna