KCPE 2006 Science

This question tested the knowledge of the urinary path in the human body. The male and female urinary systems are similar, differing only in the length of the urethra. Urine is formed in the kidneys through ultrafiltration of blood. The urine is then passed through the ureters to the bladder, where it is stored. During urination, urine stored in the bladder is then discharged through the urethra.

Fertilization takes place in the fallopian tubes/oviducts and the fertilized egg implants itself in the walls of the uterus (Part M). Part L is the ovary which is where the eggs are produced and stored until they are released ready for fertilization.

Here one needed to correctly identify the different physical changes that take place during adolescence in males and in females.

For girls, the physical changes around puberty include:

• changes in body shape and height (hips and breasts)
• growth of pubic and body hair
• the start of periods?(menstruation).

For boys, the physical changes include:

• changes in body shape and height (shoulders grow broader)
• start of wet dreams
• growth of body and facial hair
• changes to voice/ breaking of voice.

The planet nearest to the sun is Mercury while the brightest one is Venus (hence known as the evening star). The smallest planet is Mercury followed by Pluto, Mars, Venus, Earth, Uranus, Neptune, Saturn and finally Jupiter in that order.

Legumes belong to a family of flowering plants having pods(legumes) as fruits and root nodules enabling storage of nitrogen-rich material. Other well-known examples of legumes include peas, beans, clover etc.

After pollination, when pollen grains land on the stigma of a flower of the same species, a tiny tube develops on the stigma and runs down the style of the ovary. The pollen tube contains a male gamete which meets the female gamete in the ovule and when the two gametes combine, fertilization occurs and their chromosomes join.

Non-flowering plants are those that do not produce flowers or seeds. They mainly reproduce using spores or fungi, with the exception of gymnosperms that produce seeds, but not flowers. Common examples include ferns, mosses, fungi and ornamental plants.

Here, we first identify, which group consists of all the given plants as either monocots or dicots. Monocots have fibrous root system while dicots have tap root systems.

This gap is known as the diastema

In the larval stage, ticks have 6 feet, and as an adult tick, they have 8 legs. This distinguishes ticks from insects, which have 6 legs, but they have as many legs as adult mites, scorpions and spiders.

Filter-feeder birds/animals feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure.

Water softening is the process through which calcium and magnesium ions are eliminated from hard water. Methods of water softening are ion exchange, boiling/distillation, use of washing soda/lime and reverse osmosis.

We prevent spread of cholera by good hygiene practices.

Liquids which mix are known as “miscible liquids” while ?immiscible liquids? do not mix.

Solids have definite shape and definite volume, liquids have no definite shape but have definite volume, gases have no definite shape and no definite volume.

Correctly identify first that the item fixed by bacteria in the root nodules is NITROGEN and then identify the proportion of this gas in the air. Nitrogen comprises 78%, Oxygen 21%, Carbin dioxide 0.03% and rare gases 0.97%

Lightning normally strikes the highest point in an area. Fixing sharp pointed rods to tall buildings ensures that the lightning strikes the rod and is then conducted by a conductor at the side of the building safely into the ground where it would cause no harm.

A rainbow is caused by reflection, refraction and dispersion of light in water droplets resulting in a spectrum of light appearing in the sky as multicoloured arc. Rainbows caused by sunlight always appear in the section of sky directly opposite the sun. The rain droplets represents a medium with a different optical density than the surrounding air. Light waves refract when they cross over the boundary from one medium to another. The different colours refract at different angles, hence forming the rainbow.

A radio cell has stored chemical energy. When the radio is turned on, energy flows through the radio wires and circuits as electrical energy to the speaker. In the speaker coils are magnetized and the diaphragm begins to vibrate (kinetic energy) thereby generating sound.

Conduction is the process by which heat is transmitted in solids, while convection is the process by which heat is transmitted through liquid medium. In radiation, heat is transmitted in gases.

Protecting the body against diseases is the function of Vitamins. Look for the answer that has all foodstuffs given as those of the vitamins class. Proteins help in growth and body repair while carbohydrates work to provide the body with energy.

Salt absorbs water from foods by osmosis, making the environment too dry to support harmful mold or bacteria.

Eating soil by pregnant women is often related to a deficiency in iron, zinc, or another nutrient in the body.

There are three main types of pulleys: fixed, movable, and compound.

A fixed pulley?s wheel and axle stay in one place. eg. a flag pole: When you pull down on the rope, the direction of force is redirected by the pulley, and you raise the flag.

A movable pulley is a pulley that is free to move up and down, and is attached to a ceiling or other object by two lengths of the same rope. eg. construction cranes, modern elevators, and some types of weight lifting machines at the gym.

A compound pulley consists of combinations of fixed and movable pulleys.