Here are the answers to the biology questions: 1. a) The parts labelled 1-7 are: 1: Pinna* (or Auricle / Outer ear) 2: Auditory canal* (or External auditory meatus) 3: Ossicles* (Malleus, Incus, Stapes) 4: Auditory nerve* 5: Eardrum* (or Tympanic membrane) 6: Eustachian tube* 7: Cochlea* b) The velocity of sound is fastest in the middle ear, specifically through the ossicles (part 3), which are solid bones. c) Part 1 (Pinna) itself does not produce a substance. However, the auditory canal (part 2), which is part of the outer ear, produces earwax (cerumen). d) The function of part 6 (Eustachian tube) is to equalize the pressure between the middle ear and the atmospheric pressure, ensuring the eardrum can vibrate freely. e) From part 7 (Cochlea), hearing finally takes place when the vibrations are converted into electrical impulses by the hair cells within the cochlea. These impulses are then transmitted along the auditory nerve (part 4) to the brain, where they are interpreted as sound. f) Other functions of the ear apart from hearing include maintaining balance and detecting changes in body posture. These functions are primarily carried out by the semicircular canals and vestibule in the inner ear. 2. When a person's hand accidentally touches a hot object, it is quickly withdrawn due to a reflex action. This involves a reflex arc, which is the neural pathway that mediates a reflex action. Stimulus: The hot object stimulates thermoreceptors* (heat receptors) in the skin of the hand. Sensory Neuron: These receptors generate nerve impulses that travel along a sensory neuron* (afferent neuron) towards the spinal cord. Spinal Cord (Relay Neuron): In the spinal cord, the sensory neuron synapses with a relay neuron* (interneuron). Motor Neuron: The relay neuron then synapses with a motor neuron* (efferent neuron). Effector: The motor neuron carries the nerve impulses away from the spinal cord to the effector muscles* in the arm. Response:* The effector muscles contract, causing the hand to be rapidly withdrawn from the hot object. This entire process occurs involuntarily and very quickly, without conscious thought from the brain, although the brain eventually registers the sensation of pain. 3. a) Four differences between the coordination of the human eye's internal response to light and the tropic movement of a flowering plant in response to light: • Nature of Coordination: Human eye response involves nervous coordination (electrical impulses via neurons), while plant tropic movement involves hormonal coordination* (chemical signals like auxins). • Speed of Response: The human eye's response (e.g., pupillary reflex) is rapid (milliseconds), whereas plant tropic movement (e.g., phototropism) is slow* (hours to days). • Effectors: The human eye's response involves muscles (iris muscles) as effectors, while plant tropic movement involves differential cell growth and elongation* in specific tissues. • Reversibility/Duration: The human eye's response is reversible and short-term (pupil dilates/constricts as light changes), while plant tropic movement often results in permanent* changes in growth direction. b) The structure in the ear that detects: i) Sound waves is the cochlea*. ii) Change in posture is the semicircular canals and vestibule* (utricle and saccule). 4. The question regarding uniform coleoptiles is incomplete. Please provide the full question and the accompanying figure for experiments Q and R. 3 done, 2 left today. You're making progress.