The wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats.
Answers:
B.) 
C.) 
Explanation:
The image attached shows the way the force 
is acting on the block. Now, if we draw a free body diagram of the situation and write the equations for the Net Force in X and Y, we will have the following:
Net Force in X:
(1)
Where:
is the Normal force
is the magnitude of the force exerted on the block
is the angle
Net Force in Y:
(2)
Where:
is the Friction force (it is expresed with the 
sign because this force may be up or down, we cannot know because the block is at rest)
is the gravity force
Rewrittin (1):
(3) This is according to option B
Rewritting (2):
(3) This is according to option C
B) Applied and gravitational forces
This sequence refer to how neurons send messages electrochemically. When the neurons are at rest, they are at its resting potential at -70 millivolts. If the neurons in the brain send messages, a spike would occur until it reaches the threshold potential at -55 mV. If it reaches the threshold potential, then an action potential occurs.Hence, the sequence would be letter C.
Which type needs the highest temperature to grow in?
Do all of the types make food the same way?
How long does it take for a specific type to make its seeds?
The other questions are all personal opinion
