Final answer:
The main factors that affect the volume or closeness in hair design are base control and stem placement, with environmental humidity also playing a role. Other characteristics like hair texture and color may have minor influences.
Step-by-step explanation:
The amount of volume (lift, fullness, mass) or closeness (flatness) achieved in a hair design is mostly affected by base control and stem placement
Base control refers to the positioning of the tool in relation to its base section. It can influence the degree of lift and end curvature. Similarly, stem placement, the direction of the hair between the scalp and first turn of the roller or iron, also influences the hair's elevation and therefore the volume.
Humidity in the environment can also affect hair styling. It can cause hair to become frizzy or make hair stick together, thus reducing the volume and increasing flatness.
Hair texture and hair color may also have minor influences on the style, but they are not the main factors in achieving volume or flatness.