The external ear structure is called the Pinna.
The Pinna helps to channel sound waves into the ear.
Many animals have the ability to move their pinna towards the direction of sound.
I have attached an image of a dog's ear to show you the external structure called the Pinna.
I hope this helps! I'm happy to answer any other questions you might have :)
[Image sourced from: https://www.msdvetmanual.com/dog-owners/ear-disorders-of-dogs/ear-structure-and-function-in-dogs]
I think it would be the second one because some think that there is enough evidence and some do not.
Uring this period he became acquainted with Osama bin Laden, a wealthy Saudi who had joined the Afghan resistance to the Soviets,
Answer:
The correct answer is d all of the above
Explanation:
There are many reasons behind increasing the concentration of atmospheric carbon dioxide such as
1 Burning of fossil fuels such as coal,petroleum increases the level of atmospheric carbon dioxide.
2 Increase in Argiculture also increases the level of green house gases such as CO2.
3 Clearing of lands for increasing population and agriculture by cutting down trees also adversely effect the normal 02:CO2 ratio in the atmosphere.