<h3><u>Answer;</u></h3>
A. 4
<h3><u>Explanation;</u></h3>
- <em><u>The period of a wave or periodic time is the time taken for a complete oscillation to occur. </u></em>For example its is the time taken between two successive crests or troughs.
- <em><u>The beats or oscillation that occur in one second represents the frequency. Frequency is the number of complete oscillations or beats in one second in a wave.</u></em>
- Frequency, measured in Hertz is given by the reciprocal of the periodic time.
- Thus; <u><em>Frequency or beats per second = 1/(1/4) = 4</em></u>
- <u><em>Hence , 4 beats per second</em></u>
To solve this problem we will apply the concepts related to the Force of gravity from Newtonian theory for which it is necessary to

Where,
G = Gravitational universal constant
M = Mass of Earth
m = mass of Object
x = Distance between center of mass of the objects.
From this equation we can observe that the Force is inversely proportional to the squared distance between the two objects. The greater the distance, the lower the force of gravity and vice versa.

If you want to increase the force of gravity, you need to reduce the distance of the two. Therefore the correct option is B. Talk to the distance between them.
Based on the options given, the possible answer for this query is 0.450g/450kg
density of water is = 1 g/cm3density of gasoline is = 0.7 g/cm3difference is .3 g/cm3
d=m/v
derivation: m=dv
=.450 g/450kgThank you for your question. Please don't hesitate to ask in Brainly your queries.
The cell theory states that:
1) All living organisms are composed of one or more cells.
2) The cell is the basic unit of structure and organization in organisms.
3) Cells arise from pre-existing cells.
Your statement is not present, so the answer would be no.
♧
A law has always been observed to be true