Answer:
All of the above are true.
Step-by-step explanation:
According to Bohr model, the electrons orbit around the nucleus in particular orbits. These orbits have fixed energy. when electrons jump from one orbit to another, they lose or gain fixed energy. So, the first statement is true. The emission spectrum of a particular element is always same and can be used to identify element. This is used to identify the composition of stars from their spectrum. Hence, the last statement is also true.
The orbital is a region around the nucleus in an atom where is high probability for an atom to exist. According to uncertainty principle, the exact location and speed of an electron cannot be found. So, third and fourth statement are true.
Thus, the correct option is- All of the above are true.