Answer:
(D) a brief early period of hyper rapid expansion of space-time. 
Explanation:
Cosmic inflation is a theory which states that in an interval of 10⁻³⁶ seconds to around 10⁻³³ seconds after the big bang there was a massive expansion. 
According to the big bang theory the universe came to be from a singularity i.e., a point of infinite gravitational field. The universe is expanding this means that according to the conservation of energy the universe was expanding from the beginning. 
 
        
             
        
        
        
Answer:
D. 4000 km
Explanation:
f = Frequency of wave that is being transmitted = 76 Hz
 = Wavelength of wave that is being transmitted
 = Wavelength of wave that is being transmitted
v = The velocity of electromagnetic waves through air = 
Velocity of a wave is given by

Hence, the approximate wavelength of the waves is 4000 km
 
        
             
        
        
        
The given mass is 0.025563 g.
Examine the given choices.
a. 0.026 g
This uses 2 significant digits, with rounding to the 3rd decimal place.
b. 2.5 x 10² g = 250 g.
It is incorrect.
c. 0.025 g.
This uses 2 significant digits. It is inaccurate because it does not use rounding to the 3rd decimal place.
d. 0.02 g
This uses one significant digit. It is incorrect for representing the given data.
Answer: a.  0.026 g
        
             
        
        
        
It's a quantitative observation because it includes numerical data.