Answer the conditions necessary for photosynthesis.

The conditions necessary for photosynthesis are:

• Carbon dioxide
• Water
• Sunlight (light energy)
• Chlorophyll

Two differences between an animal cell and a plant cell are:

• Plant cells have a cell wall outside the cell membrane, while animal cells do not.
• Plant cells contain chloroplasts for photosynthesis, while animal cells do not.
• Plant cells typically have a large, central vacuole, whereas animal cells have small, temporary vacuoles or none.
• Plant cells have a fixed, rigid shape, while animal cells have an irregular shape.

a) Challenges of menstruation faced by girls:

• Lack of access to sanitary products, leading to discomfort and potential health issues.
• Social stigma and cultural taboos, causing embarrassment and limiting participation in daily activities.
• Menstrual pain (dysmenorrhea) and other physical symptoms that can disrupt school attendance and daily life.
• Lack of proper sanitation facilities in schools and public places.

b) Two examples of STIs:

• Chlamydia
• Gonorrhea
• Syphilis
• HIV/AIDS
• Herpes

• Diffusion is the net movement of particles from an area of higher concentration to an area of lower concentration. In living things, it is crucial for the exchange of gases (oxygen and carbon dioxide) in the lungs and tissues, and for the absorption of nutrients in the small intestine.
• Osmosis is the net movement of water molecules across a selectively permeable membrane from a region of higher water potential to a region of lower water potential. In living things, it is vital for water absorption by plant roots, maintaining turgor pressure in plant cells, and regulating water balance in animal cells.

The importance of fertilization in reproduction is:

• It restores the diploid number of chromosomes by combining the haploid nuclei of the male and female gametes.
• It initiates embryonic development by activating the egg.
• It introduces genetic variation by combining genetic material from two different parents, leading to offspring with unique traits.

a) Definitions:

• Renewable energy is energy derived from natural processes that are replenished constantly.
• Non-renewable energy is energy derived from sources that are finite and cannot be replenished on a human timescale.

b) Examples:

• Examples of renewable energy: Solar energy, wind energy, hydroelectric power.
• Examples of non-renewable energy: Coal, petroleum (oil), natural gas.

• Pressure is defined as the force applied perpendicular to the surface of an object per unit area over which that force is distributed.
• Its SI unit is the Pascal (Pa). $$P = \frac{F}{A}$$ where $P$ is pressure, $F$ is force, and $A$ is area. The unit Pascal is equivalent to Newtons per square meter ($\text{N/m}^2$).