I think there is a very subtle difference. hand and hand just refers to two hands not necessarily together.
hand in hand implies that the hands are connected or together.
An arm is what you used to type the question. The hand is what I used to type this answer.
The difference between internal and external validity is in their nature. Internal validity indicates if a study depicts relation between two variables. External validity on the other hand generalizes the study of the variables.
Equilateral deals with equal sides. Equiangular, on the other hand, deals with angles, Equal Angles.
difference between as on and as at
Get a container that has markings for how much liquid is in it. Fill it half way with water, and write down how full it is. Then stick your hand in the water and measure the new water level. The difference between the two water levels is the volume of you hand.
difference between hand drawings and digital art
The difference between handwashing and hand sanitazation is that hand washing is youre washing youre hand with water and soap and hand sanitazation is using hand sanitazer or using those sanizatized wipies
the difference between a puppet and a cartoon is that a puppet has to be used by hand and a cartoon is animated on computer
"At hand" means something is nearby or readily available. "On hand" means something is physically present or available for immediate use.
An arm is what you used to type the question. The hand is what I used to type this answer.
what is the difference between roughage and succulents
One works with left hand, other works with right hand
Hand off
2mm in case length.
By touching or by feeling
a smack is with the back of your hand slap is with the front.
hand position