Answer: a. both reliable and valid
The parameters used to describe a particular trait or characteristic in a human behavior should be reliable and valid, in order to determine the response of the population with respect to a particular stimulus.
Answer: Oblique impact
Explanation:
When the motion of one or both of the particles is at an angle to the line of impact, the impact is said to be oblique impact.
On the other hand, when the directions of motion of the two colliding particles are moving along a line of impact, then it's refered to as central impact.
(a) We can find the current flowing between the walls by using Ohm's law:

where

is the potential difference and

is the resistance. Substituting these values, we get

(b) The total charge flowing between the walls is the product between the current and the time interval:

The problem says

, so the total charge is

The current consists of Na+ ions, each of them having a charge of

. To find the number of ions flowing, we can simply divide the total charge by the charge of a single ion:
B. to show that there was conflict between what scientists were observing about the universe and what religion taught them