Answer:
may be A.................. ....
Answer:
Subbituminous coal can form at temperatures as low as 35 to 80 °C (95 to 176 °F) while anthracite requires a temperature of at least 180 to 245 °C (356 to 473 °F).
Sub-types: Cannel coal
Child material class: Lignite
Explanation:
Answer:
B) Conduction requires two objects to be in physical contact.
Explanation:
Conduction is when two objects are directly touching each other. So, the objects must come in physical contact with each other.
Answer:
1.Velocity and pitch
2.The unit of vibration is hertz. The number of oscillations of an oscillating body per second is known as frequency. Complete step by step answer: The time taken by a vibrating body to complete one vibration is time period.
3.Frequencies above 20,000 Hz are known as ultrasound.