Answer:
b. 0.75 mm
Explanation:
The distance between antinodes d is half the wavelength
. We can obtain the wavelength with the formula
, where f is the frequency given (
) and v is the speed of sound in body tissues (v=1540m/s), so putting all together we have:

which is very close to the 0.75mm option.
The three main cycles of an ecosystem are the water cycle, the carbon cycle and the nitrogen cycle.
Explanation:
It is given that,
Weight of the rock in air, W = 110 N
Since, W = mg


m = 11.22 kg
We need to find the apparent weight of the rock when it is submerged in water. Apparent weight is equal to the weight of liquid displaced i.e.

d is the density of water, 
V is the volume of rock, 

M = 3.37 kg
The apparent weight in water, W = m - M

W = 76.93 N
So, the apparent weight of the rock is 76.93 N. Hence, this is the required solution.
The work done by the friction force to stop the player is equal to his loss of kinetic energy:

The work done by the friction force is the magnitude of the force

times the distance covered by the player, d:

The loss in kinetic energy is simply equal to the initial kinetic energy of the player, since the final kinetic energy is zero (the player comes to rest):

Substituting into the first equation, we get:

from which we find d, the distance covered by the player: