Suggested Answer:(a)Sample Answer:
Bird
- Aerofoil wing – to generate the upward llift
- A pair of antagonistic muscle( pectorolis major and minor) for upstroke and downstroke //pulled down and up the wings.
- Single organ(one testes/kidney)//small skull//hollow bone//no teeth – to reduce weight.
- Streamlined body shape// Feathers facing the posterior/backward – to reduce air resistance
- Waterproof feather to avoid increase in body weight during raining.
- Streamlined body shapes/overlapping scales facing the posterior/slimy coating – to reduce water resistance
- Myotome muscles are are W/V- shaped which act antagonistically
- Swim bladder/air sac – maintain buoyancy in water.
- Fins
- -Dorsal and ventral fin – to prevent yawing and rolling
- -Caudal/tail fin – provides thrust and controls direction
- -Pelvic fin and pectoral fin- act as brakes
[Any 4]
(b)Submerged plants
- Posses air sacs within the leaves and the stem to help the plant to stay upright in water
- Water buoyancy provides support
- Have very few vascular tissue/woody tissue
- Thin/narrow/flexible leaves to provide little resistance to water flow
Floating plants
- Stem have plenty of air sacs
- Aerenchyma tissues which help to stay afloat in water.
- Do not have woody tissues
- Natural water buoyancy to helps them to float
- Have broad leaves that are firm but flexible to resist being torned by wave action.
[ Any 3]
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