Answer:
D. By adding the vectors

Explanation:
Given
Represent the velocity of the river current as VR

Represent the velocity of the boat as VB

Required
How to calculate the velocity of boat relative to river current
From the question, we understand that both move in the same direction.
So, the relative velocity V is calculated as:



Notice that the both velocities are added together to get the relative velocities.
This is so because they both move in the same direction
<em>From the list of given options, only option D is correct.</em>
Answer:
to describe
Explanation:
Based on the scenario being described within the question it can be said that in this research the Professor is utilizing the goal of to describe. This refers to trying to describe a specific behavior or phenomenon in order to use that description as a basis for learning more about that specific behavior or phenomenon. Which in this scenario would be the children complaining about not getting a turn on the carousel.
Trade flourished because these progressing empires were developing new ways to produce products and utilize agriculture in their areas, such as Han with silk and Rome with olives and fishing/seafaring. These empires has never had access to goods that were from other areas before the Silk road, causing trade to become immensely popular and relied upon.