In which spectral sequence are the hottest stars categorized?

In which spectral sequence are the hottest stars categorized?
 
  a. O stars
  b. B stars
  c. A stars
  d. F stars
 e. K stars

Question 2

During Solar System formation, solid particles contracted from the gas of the nebula as it cooled.
 
  a. True
  b. False
  Indicate whether the statement is true or false

Question 3

Which star has the largest diameter?
 
  a. white dwarf
 b. main sequence
  c. red giant
 d. supergiant
 e. regular giant

Question 4

The inner planets are composed of rock and metal, and the outer planets are rich in low-density gases such as hydrogen and helium.
 
  a. True
  b. False
  Indicate whether the statement is true or false

Question 5

Which star has the highest density (mass per unit volume)?
 
  a. white dwarf
 b. main sequence
  c. supergiant
 d. red giant
 e. regular giant

Question 6

The passing star hypothesis suggests that planets form in the rotating disks of gas and dust around young stars.
 
  a. True
  b. False
  Indicate whether the statement is true or false

Question 7

Our Sun's spectral temperature type is classified as a(n) ____ on the spectral sequence.
 
  a. O star
 b. F star
 c. G star
 d. K star
 e. M star