USA had to join the war after altercations and provocations by the Germans.
Explanation:
America had remained neutral for almost all of the war until their trade ships began being sunk by the Germans as USA was a major supplier of arms to the nations and then their trade routes were purposefully blocked.
There was also a plan revealed in the Zimmermann note about a conspiracy to get Mexico to declare war on the USA effectively starting a home front in the war for US.
This was what led US to get involved in the war directly.
So hmm the distances are clearly 6km and 15km anyway
so hmmm alrite.. recall your d = rt, or distance = rate * time
if the rate of speed of the tourist's boat is say "r", on the river, against the stream, is not going to be "r" but we have to subtract the river's speed, since we know is "2", thus the speed of the boat is " r - 2"
now, off he goes on the lake, however, the lake is just still water, so, on still water, his speed is indeed just "r"
if he sailed "t" time in the river, on the lake was 1 extra hour, or " t + 1 "
thus

solve for "r"
False- Homogamy is the marriage between the same sex.
Answer:
C. National policy of taking over and ruling other lands.
Explanation:
got it right on edg
Researchers want to see if an athlete's diet affects his speed. Thirty participants are given either a carbohydrate loaded diet or a protein loaded diet, and their speeds on a 100-meter dash are recorded. This study is an example of an experiment study.
<h3>What is an experiment study?</h3>
An experiment study refers to study of a group of samples in which a researcher introduces new concept and discuss their outcomes over a group of people.
Cause and effect can be established through experimental inquiry. Researchers can examine different cause-and-effect linkages that a product or idea can produce through the modification of factors.
A treatment is imposed on people during an experiment. Here, the diet is considered as treatment.
Learn more about experiment study, here:
brainly.com/question/15938198
#SPJ1