I believe it’s B. Electrons
Hi there!
Two possible answers are air resistance and friction.
Friction is caused by the rubbing of the surface of the ground and the surface of the object. Although ice doesn't have much friction, it can still cause friction.
Air resistance is caused by friction between the air and the object. As the object moves along a surface, it collides into many air particles; thus, it slows down.
Hope this helps.
Have an awesome day! :)
Answer:

Explanation:
Given data:
weigh (head+arms + head) w_1 = 438 N
centre of gravity y_1= 1.28 m
weigh (upper leg) w_2 = 144 N
Center of gravity y_2 = 0.760 m
weigh ( lower leg + feet) = 87 N
centre of gravity = y_3 = 0.250 m
location of center of gravity 


Regardless of what direction an object is moving, the acceleration
due to gravity is always directed toward the center of the Earth.
That's the direction commonly known as "down".
Answer:
a
Explanation:
b, c, and d are all opinion based, a is the only one that you need factual evidence and observations.