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B2 Topic 3 Common systems
Fossils and evolution

Fossils are the preserved traces of organisms that lived millions of years ago.
Fossils are formed in 3 ways:
o A buried organism in soft material such as clay decays and leaves a cast/imprint of the organism.
Footprints can be preserved this…

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Percentile charts

Growth charts are used to assess a child's growth over time so that an overall pattern in development can be
seen and any problems highlighted (e.g. obesity, malnutrition, dwarfism etc.)
For example, a baby's growth is monitored after birth to check they are growing normally. They are plotted…

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These help fight disease.
Some types can engulf and digest pathogens (phagocytes). Others (lymphocytes) produce antibodies
(proteins that bind to pathogens to destroy then) and antitoxins to neutralise any toxins produced byt he
microorganisms.
A low WBC count could increase risk of infection while a high count could mean you…

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Here's how the blood flows through the heart:
1. Vena cava brings deoxygenated blood from the whole body into the right atrium.
2. The right atrium contracts and forces the blood into the right ventricle, through the valves. Valves
prevent the back flow of blood.
3. When the right ventricle…

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2. Oesophagus: a muscular tube between the mouth and the stomach. The muscles contract in waves to
squeeze the food down; this is called peristalsis.
3. Stomach: muscular bag that produces acid and enzymes (mostly protease). It churns up food with these
juices by peristalsis to make a thick paste.…

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o Circular muscles which surround the gut
o Longitudinal muscles running down the length of the gut.
The muscles squeeze food along which is called peristalsis.
Waves of circular muscle contractions push food along the gut.
Waves of longitudinal muscle contractions run slightly ahead to keep food in a ball.…

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Probiotics

These contain live bacteria such as Lactobacillus and Bifidobacteria which are `friendly'. They are similar to
those found naturally in the gut and produce lactic acid.
They are added to foods such as yoghurt, soya milk and dietary supplements.
They are claimed to improve your digestive system and makes…

Comments

Swallowtail

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A very detailed set of notes with some nice diagrams. The diagram of the heart with the blank labels would be a useful learning tool. The notes cover the digestive system, cells, tissues and organs,blood, evolution and growth so would be useful for a number of different specifications.

SMARTREVISE

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Sick

Veyrondreamer

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These notes are exemplary. That A* is thoroughly deserved!

Aishah1234

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Can you make B2 Topic 1 & 2?

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