Answer:
Electromagnetic waves differ from mechanical waves in that they do not require a medium to propagate. This means that electromagnetic waves can travel not only through air and solid materials, but also through the vacuum of space.
Explanation:
Answer:t=0.81 s
Explanation:
Given
Penguin slides down with constant velocity of 3.57 m/s
as the Penguin Slides with constant velocity therefore
is zero on Penguin

friction Force

coefficient of Kinetic friction



after reaching on floor final velocity of penguin will be zero after time t
thus

here 
(deceleration)



Concentration involves the relative amounts of solvent and solute in a solution, when strength is related to the extent to which a substance dissociates :))
i hope this is helpful
have a nice day
Answer:
Option b, pothographs from drones.
Explanation:
the USGS (U.S. Geological Survey) decided to make photographic captures from drones to the volcanic surfaces, which allowed through observations to understand things like the characteristics of the lava, the height of the volcanic plumes (among others).
Podemos ver en el siguiente enlace un ejemplo de fotografía tomada desde un dron al Kilauea.
https://www.usgs.gov/media/images/k-lauea-volcano-drone-over-lava-channel