Crystalloid and colloid differ with respect to:
This question has multiple correct options.
(a)- Tyndall effect
(b)- Particle size
(c)- Diffusion through animal or vegetable membrane
(d)- The number of particles per unit volume of solution

Hint: Crystalloids are salt solutions having small molecules and when they are injected into the body they can travel easily and colloids are those particles whose size ranges between 1nm to 1000nm.

Complete Solution :
Let’s discuss crystalloid and colloid to get our answer,
Crystalloids - Crystalloids are the aqueous solution of salts and minerals that can be crystallized.
Example - salt, sugar, urea.
They have a smaller particle size compared to colloids (<1nm).
These are homogenous systems.
They don’t show the Tyndall effect.
These are classified as isotonic, hypertonic, and hypotonic.
These can be stored at room temperature.
They can quickly pass through the animal or vegetable membrane
Preparation of Crystalloids is very easy and they have a long life span.

Colloids - Colloids are the homogenous no-crystalline substance containing large molecules or ultramicroscopic particles of one substance dispersed in a second substance. Colloids include gels, sols, and emulsions. These particles can not be separated by ordinary filtration.
Example - starch, gelatin, gum
They have a much larger particle size compared to Crystalloids (1-200 nm).
These are heterogeneous systems.
They don’t show the Tyndall effect.
These are classified as lyophilic and lyophobic.
These should be stored in refrigerators.
They cannot pass through the animal or vegetable membrane.
Preparation of colloids is not very easy and they have a short life span.

Both of them have a different number of particles per unit volume of solution. Because in crystalloids, particles are smaller compared to colloidal particles. Hence, per unit volume there would be more crystalloid particles compared to colloids.
So, the correct answer is “Option A,B,C and D”.

Note: There is another similar phenomenon related to colloids, which is suspension. A suspension is identifiable because its particles are large and settle out of the dispersing medium due to the effects of gravity. The dispersed particles of a colloid are intermediate in size between those of a solution and a suspension.