Answer:
The statement that says the cranial meninges have three layers of the dura mater is false.
Explanation:
The meninges are protective layers located between the central nervous system and its bone protection, both at the level of the brain and the spinal cord. The brain and spinal cord are surrounded by three membranous layers (cranial meninges), these are the dura mater, arachnoid mater and the pia mater, they are located one below the other.
The dura mater is the outermost strong fibrous tissue layer, formed by two layers of which the outermost one is attached to the bone and represents its periosteum. The innermost layer joins the arachnoid membrane. In addition to being the outermost meningeal, the dura mater is the hardest and most condensed of the three we have. Attached in part to the skull, this membrane protects the brain and acts as a structural support to the entire nervous system by dividing the cranial cavity into different cells.
The arachnoid mater, located in an intermediate zone between dura and pia mater, through this meninge and the space between arachnoid and pia mater it’s where the cerebrospinal fluid circulates; and protects the central nervous system against injuries.
The pia mater is the most internal, flexible meninge and in the greatest contact with the structures of the nervous system. In this layer you can find numerous blood vessels that supply the nervous system structures.
The spinal meninges are inside the spinal canal and encase the spinal cord. They have the same basic structure as the cranial meninges, composed of three layers: the dura mater, the arachnoid mater and the pia mater.
Chromatography is a laboratory technique for the separation of mixture. It contains two components:
Stationary phase- substance that is fixed inside the column
Mobile phase- substance that is moving through the column.
Analyte is the mixture that has to be separated by chromatography.
When both are added to the column, mobile phase and analyte, components of the analyte will adhere to the stationary phase at different level and as a result travel at different speeds through the stationary phase as the mobile phase flows through it. The components that adhere more strongly to the stationary phase travel more slowly compared to those with a weaker adhesion. So, chromatography separate substances based on their adhesion for stationary phase.
Answer:
The tiny muscles that make up the iris, known as the circular and radial muscles, relax and contract to maintain a fairly constant level of light entering the eye. In bright light, the circular muscles contract whilst the radial muscles relax. This causes the pupil to constrict and less light enters the eye.
Explanation:
Answer:
Producers ( also called autotrophs) are the organisms that synthesize their own ( glucose) food using carbon dioxide and water in the presence of sunlight ( photosynthesis). They use energy from sunlight to convert it into chemical energy ( that is stored in the glucose). Autotrophs occupy the base of a food chain within the ecosystem as they are first trophic level for the energy transfer.
Decomposers ( such as bacteria and fungi that act on dead plants and animals) can recycle the organic matter back into the food web and biogeochemical cycles in the form of nutrients such as carbon and nitrogen.
Thus, the correct answers are-
1) Producers
2) Decomposer
3) Sunlight
4) Base
