A) How do humans differ from other mammals?

Here's the solution to question 1 in English:

a) How do humans differ from other mammals?
Humans differ from other mammals in several key ways:

• Bipedalism: Humans are obligate bipeds, meaning they walk upright on two legs, freeing their hands for other tasks. Most other mammals are quadrupedal.
• Larger, more complex brain: Humans possess a significantly larger and more developed cerebral cortex, enabling advanced cognitive abilities like abstract thought, complex problem-solving, and self-awareness.
• Complex language and culture: Humans have a unique capacity for complex spoken and written language, allowing for intricate communication and the development of diverse cultures, traditions, and cumulative knowledge.
• Reduced body hair: Compared to most other mammals, humans have significantly less body hair, which is thought to be an adaptation for thermoregulation.

b) State two functions of each of the following cell organelles:

• (i) Nucleus:
  1. Stores the cell's genetic material (DNA) in the form of chromosomes.
  2. Controls cell growth, metabolism, and reproduction by regulating gene expression.
• (ii) Mitochondrion:
  1. Generates most of the cell's supply of adenosine triphosphate (ATP), used as a source of chemical energy, through cellular respiration.
  2. Plays a role in cell signaling, cellular differentiation, and cell death (apoptosis).
• (iii) Endoplasmic reticulum (ER):
  1. Rough ER: Synthesizes and modifies proteins destined for secretion or insertion into membranes, studded with ribosomes.
  2. Smooth ER: Synthesizes lipids, metabolizes carbohydrates, and detoxifies drugs and poisons.
• (iv) Lysosome:
  1. Breaks down waste materials and cellular debris through enzymatic digestion.
  2. Digests worn-out organelles and foreign invaders like bacteria and viruses.

c) Define each of the following terms:

• (i) Diffusion: The net movement of particles from an area of higher concentration to an area of lower concentration, down a concentration gradient, until equilibrium is reached.
• (ii) Osmosis: The net movement of water molecules across a selectively permeable membrane from a region of higher water potential (lower solute concentration) to a region of lower water potential (higher solute concentration).
• (iii) Active transport: The movement of molecules or ions across a cell membrane against their concentration gradient, from a region of lower concentration to a region of higher concentration, requiring energy (usually from ATP).