Horizontal is from side to side. Vertical is from top to bottom.
The correct answer is D, this is 'present perfect' tense. It is formed with the use of the verb HAVE in present simple tense (so, HAVE/HAS), and the past participle of a verb (or the third column of irregular verbs).
A cannot be correct, because then it would say - I hear.
B cannot be correct, because then it would say - I had heard.
C cannot be correct, because then it would say - I heard.
And since there is also HAVE HEARD, the correct answer has to be D.
1. Sun is a big star that provides heat and light to the whole solar system.
2. Sun is 140 miliion km away from Earth.
Answer: It
Explanation: Because the car is an object.