The guidelines for making good and accurate observations are:
1. Standardise the experimental setup: Know the precision and the accuracy of the instrument used to make observations. Example, thermometer with a least count of 1°C cannot measure in fractional values.
2.Take careful measurements: Holding the instrument properly without causing any disturbance is the key.
Cell, tissue, organ, organ system, organism if that’s what you are referring to
it is D on my point of veiw..
Answer: Option A "Choroid plexus".
Explanation:
Cerebrospinal fluid can be defined as the fluid that is found in the brain and spinal cord of human beings. It is a clear and colorless fluid.
The production of cerebrospinal fluid takes place by the specialized ependymal cells that lies in the choroid plexuses which is present in the ventricles of brain.
The amount of cerebrospinal fluid in a day is 500mL. This fluid acts as cushion that protects the brain from mechanical and immunological protection.
Hence, the correction answer is option A
D because kg is mass and cubic cm is volume which Density = Mass / Volume