The Scientific Method

• Scientific Method is a process of investigation where problems are identified and their explanations are tested by carrying out experiments.
• Observation : An unbiased, accurate report of an event.
• Hypothesis : An educated guess based on observations.
• Experiment : An experiment is designed to test a hypothesis.
• Data : Consists of measurements, observations/information gathered during an experiment.
• Replicate : A repeat of an experiment.
• Control : A comparison used to provide a standard against which the actual experiment can be judged.
• Theory : A hypothesis that has been supported by different experiments.
• Principle/Law : A theory that... (More)

• The heart is the pump of the circulatory system.
• It is made of cardiac muscle which does not tire.
• Cardiac muscle receives its own blood supply through the coronary arteries and veins.
• The septum divides the heart into right and left sides.
• The heart has four chambers; right atrium, right ventricle, left atrium, left ventricle.

Blood Flow Through the Heart

1. The blood flows into the vena cava into the right atrium. It is deoxygenated blood.
2. The valves open and allow the blood flow into the right ventricle. The valves close.
3. The right ventricle contracts, valves open and blood is pushed... (More)

Mouth

• This is where the food enters the digestive system[ingestion].
• Two types of digestion occur here; physical digestion and chemical digestion.
• Physical digestion is the mechanical breaking up of food into smaller pieces by the teeth. It occurs in the mouth and stomach.
• Chemical digestion is the breaking down of large food molecules into smaller ones using digestive enzymes which are produced in the mouth.

Oesophagus

• The food is swallowed and passes on to the oesophagus.
• Food is pushed down the oesophagus by a wave of muscular contraction called peristalsis.[ The food is now called a bolus]

The Stomach

• The... (More)

EXPLAIN THE TERM IN VITRO FERTILISATION

Involves removing eggs from the ovary and fertilising them outside the body.

SUGGEST A REASON FOR THE REMOVAL OF SEVERAL EGGS

A number of eggs are removed to increase the chances of fertilisation occurring and getting an embryo to implant.

IDENTIFY A GERM LAYER FROM WHICH THE SKIN OF THE DEVELOPING EMBRYO ARISES ?

Ectoderm

FROM WHICH TISSUES DOES THE PLACENTA FROM

The placenta is formed from the chorion (the outer membrane of the embryo) and the mother’s blood vessels.

EXPLAIN WHY MIXING MUST NOT OCCUR

Blood groups may be different types, if their... (More)