Answer:
No one can see in total darkness. Fortunately, there’s almost always some light available. Even if it’s only dim starlight, that’s enough for your eyes to detect. What’s truly amazing is how little light is required for you to see.
Human eyes have two main features that help us see better in low light: the pupil’s ability to change size, and the eye’s two types of light-sensing cells.
Opening up to let in more light
Your pupils are the black areas at the front of your eyes that let light enter. They look black because the light that reaches them is absorbed inside the eyeball. It’s then converted by your brain into your perceptions of the world.
You’ve probably noticed that pupils can change size in response to light. Outside on a bright sunny day, your pupils become very small. This lets less light into the eye since there’s plenty available
7. Stress is the force applied to a rock, which may cause deformation of the rock. There are three major types of stress and go along with the three types of plate boundaries; Compression stress is common at convergent boundaries, tension stress at divergent boundaries, and the shear stress at transform boundaries. In this case the rocks have undergone tensional stresses.
8. Horst is a raised fault block bounded by normal faults. A horst is a raised block of the Earth's crust that has lifted, or has remained stationary, while the land on either side (garben) has subsided. Therefore the structure labeled A in the diagram is Horst.
9. A Graben; it is a valley with a distinct escarpment on each side caused by the displacement of a block downward. It often occurs side by side with the horsts. Horst and Graben structures indicate tensional forces and crustal stretching. Therefore, the structure labeled B is Graben.
The best answer would be:
Unconditioned stimulus
In Pavlov's experiment on conditioning the food was the unconditioned stimulus that triggers a reflex or natural behavior. Think of it like something that makes you do something automatically.
For example, the food. When the dog smells food, it salivates. This is unconditioned because without teaching the dog, it automatically responds by salivating.
When muscles are required to work harder than they're used to or in a different way, it's believed to cause microscopic damage to the muscle fibres, resulting in muscle soreness or stiffness.
