ANSWERS to some queries posted..

Reminders for some topics:
a. Genetics: Remember that we may not get an exact 3:1/1:1 ratio all the time, especially with small numbers of offspring. This is due to random fertilisation, where any 1 male gamete can fertilise any 1 female gamete. But the ratio can be used to predict probability (in fractions) or chance (in percentage). The ratio is only observed with a large number of offspring (eg. Mendel's experiments with peas usually dealt with a few thousand offspring).

b. Tissue: Group of cells that perform a specific function.
Organ: Group of tissues that work together to perform a specific function or group of functions.
System: Group of organs that work together for a specific purpose.

c. Microscope slide preparation (For those who keep asking): Basically it should be tested under PRCATICAL instead. But... just in case, its just placing a thin slice of specimen on the slide, add a drop of water or stain (methylene blue/iodine), then lowering the coverslip at an angle slowly so that no air bubbles form. Dry slide before viewing.

d. Qn on: State three ways in which the movement of the hand away after touching a hot object differs from a deliberate decision to lower the arm.
1. This action requires a stimulus (heat/pain) while a deliberate decision does not require a stimulus;
2. This action requires a receptor to detect the stimulus, while a deliberate decision does not require a receptor;
3. Involves a pathway through the spinal cord and does not directly involve the brain, while a deliberate decision would involve a nervous impulse that originates from the brain;
4. Not under conscious control/involuntary, while the deliberate decision would be under conscious control/voluntary;