The biological structure shown is part of one of the systems in the body - HSC - SSCE Biology - Question 31 - 2014 - Paper 1

1. A stimulus activates a receptor.
2. The receptor sends a message to the central nervous system.
3. The brain processes the information and sends a response to the effector organ to generate a reaction.

1. Sound energy in the air enters the outer ear (pinna).
2. This transforms into mechanical energy as it vibrates the eardrum.
3. The mechanical energy is transmitted through the ossicles (ear bones).
4. It then moves as mechanical energy to the oval window.
5. The movement of the oval window creates waves in the fluid of the cochlea, transforming it into mechanical energy.
6. Finally, this mechanical energy is converted into electrochemical energy in the auditory nerve.

Humans have two main types of photoreceptor cells: rods and cones.

1. Rods are responsible for vision in low light conditions and do not detect color, while cones function in brighter light and are responsible for color vision.
2. Rods are more sensitive to light but have lower spatial acuity, while cones provide high-resolution images and enable color differentiation.
3. Both types of photoreceptors work together to enhance visual perception under varying conditions, enabling humans to see across a range of environments.