A) Explain the following processes involved in the hydrologic/water cycle.

Here are the answers to questions 4 and 5:

4. a) Explain the following processes involved in the hydrologic/water cycle.

i. Transpiration
Transpiration is the process by which moisture is carried through plants from roots to small pores on the underside of leaves, where it changes to vapor and is released into the atmosphere. It is essentially evaporation of water from plant leaves.

ii. Condensation
Condensation is the process where water vapor in the air changes into liquid water. This occurs when warm, moist air cools, causing the water molecules to slow down and clump together, forming clouds, fog, or dew.

iii. Runoff
Runoff is the flow of water over land, usually from rain, melted snow, or other sources, that is not absorbed into the ground or evaporated. This water flows into streams, rivers, lakes, and eventually oceans.

b) List the four (4) main stages of fertilization in human beings.

The four main stages of fertilization in human beings are:

1. Sperm capacitation and activation: Sperm undergo physiological changes in the female reproductive tract, becoming capable of fertilizing an egg.
2. Sperm binding to the zona pellucida: Sperm attach to the outer layer of the egg (zona pellucida).
3. Acrosome reaction and penetration: Enzymes released from the sperm's acrosome digest a path through the zona pellucida, allowing the sperm to reach the egg membrane.
4. Fusion of sperm and egg membranes: The sperm and egg cell membranes fuse, and the sperm nucleus enters the egg cytoplasm, leading to the formation of a zygote.

5. a) Explain how light travels.
Light travels as electromagnetic waves in straight lines, radiating outwards from its source. It does not require a medium to travel and can move through a vacuum at a constant speed, approximately $3 \times 10^8$ meters per second.

b) State and explain any three (3) forms of light.

1. Visible Light: This is the portion of the electromagnetic spectrum that is visible to the human eye, ranging from red to violet. It allows us to perceive colors and objects.
2. Infrared (IR) Light: Infrared light has longer wavelengths than visible light and is associated with heat. It is used in remote controls, thermal imaging, and night vision devices.
3. Ultraviolet (UV) Light: Ultraviolet light has shorter wavelengths than visible light and carries more energy. It is responsible for sunburns and is used in sterilization, tanning beds, and forensic analysis.
4. X-rays: X-rays have very short wavelengths and high energy, allowing them to penetrate soft tissues but be absorbed by denser materials like bone. They are widely used in medical imaging.
5. Radio Waves: These have the longest wavelengths in the electromagnetic spectrum and are used for broadcasting radio and television signals, as well as in wireless communication.

c) State three (3) factors that affect freezing.

1. Temperature: The most significant factor; freezing occurs when the temperature of a substance drops to its freezing point.
2. Pressure: For most substances, an increase in pressure slightly raises the freezing point, while a decrease in pressure lowers it. (Water is an exception, where increased pressure lowers its freezing point).
3. Presence of Impurities/Solutes: Dissolved substances (impurities or solutes) in a liquid lower its freezing point, a phenomenon known as freezing point depression.