A light-year is a unit of distance.
The definition of a light-year is the distance light travels in one year.
I can help you with 5. 5 is a displacement-time graph.
At A it is moving in a positive direction and speed is constant.
At B it is stationary or at rest.
At C, movement is negative and it is decreasing or decelerating
At D, it’s a general downwards movement in the negative direction that can be described as overall constant
Answer:
a) > x<-c(1,2,3,4,5)
> y<-c(1.9,3.5,3.7,5.1,6)
> linearmodel<-lm(y~x)
And the output is given by:
> linearmodel
Call:
lm(formula = y ~ x)
Coefficients:
(Intercept) x
1.10 0.98
b) 
And if we compare this with the general model 
We see that the slope is m= 0.98 and the intercept b = 1.10
Explanation:
Part a
For this case we have the following data:
x: 1,2,3,4,5
y: 1.9,3.5,3.7,5.1, 6
For this case we can use the following R code:
> x<-c(1,2,3,4,5)
> y<-c(1.9,3.5,3.7,5.1,6)
> linearmodel<-lm(y~x)
And the output is given by:
> linearmodel
Call:
lm(formula = y ~ x)
Coefficients:
(Intercept) x
1.10 0.98
Part b
For this case we have the following trend equation given:

And if we compare this with the general model 
We see that the slope is m= 0.98 and the intercept b = 1.10
Explanation :
Takumi wears sunscreen and a hat each time he works in the yard. This is to protect himself with the strong radiation coming from the sun. UV rays that are coming from the sun are the main cause of skin cancer.
Stochastic effects are the effects that are caused by chance. Cancer is one of the main stochastic effects.
So, the correct option is (b) "the severity of stochastic effects, such as cancer".