A+
Val allen belt
The gas you are referring to might be ozone. The effect caused by ozone in the upper atmosphere is the formation of the ozone layer. This layer protects Earth by absorbing the majority of the sun's harmful ultraviolet radiation.
The lower atmosphere, also known as the troposphere, is the layer closest to the Earth's surface where weather events occur. The upper atmosphere includes the stratosphere, mesosphere, thermosphere, and exosphere, extending from the troposphere to space. The upper atmosphere plays a role in processes like ozone formation and protecting Earth from harmful solar radiation.
the outer layer of the suns atmosphere is the corona
exosphere
Van Allen Belt. A+
The horseshoe-shaped ring formation in the atmosphere is called the "polar vortex." It is a large area of low pressure and cold air that typically sits over the Earth's polar regions. The polar vortex can weaken or become distorted, leading to shifts in weather patterns and bringing cold air southward.
Val allen belt
kingman reef
The "horseshoe crabs" get their nickname because their arc shaped exoskeleton. The nickname is not a proper name and therefore does not require capitalization.
le Palais de Chaillot
horseshoe
If you are referring to the crossword puzzle hint, try Atoll.
The Battle of Horseshoe Bend was in Alabama, though it was a battle in name only as the Creeks were pretty much slaughtered. The name refers to a horseshoe-shaped bend in the Tallapoosa River which the Creeks had fortified, but their defenses were easily breached by Jackson's US forces in 1814.
horseshoe
Hipposandal
the golden horseshoe curves like a horseshoe around the western end of lake ontario, which is one of the reasons for its name.