The ability to reproduce is essential for a species, but not for an individual. There are some people that can't reproduce, but they're still alive!
Answer : The significant digit is 6
Explanation :
Multiply
by 
Now, on multiplying


Now, the significant digit is 6.
Hence, this is the required solution.
Answer:
The value is
Explanation:
From the question we are told that
The power output from the sun is 
The average wavelength of each photon is 
Generally the energy of each photon emitted is mathematically represented as

Here h is the Plank's constant with value 
c is the speed of light with value 
So
=>
Generally the number of photons emitted by the Sun in a second is mathematically represented as

=> 
=>
Answer:
Vector, in physics, a quantity that has both magnitude and direction. It is typically represented by an arrow whose direction is the same as that of the quantity and whose length is proportional to the quantity's magnitude. Although a vector has magnitude and direction, it does not have position.
Explanation:
The only thing I found in my notes for this question was this although it isn't in your choices, I just hope this helps you and hope you get it right!