Answer:
At different times
Explanation:
The echo returns at different times, but faster in water. This is because water particles are bound closer and this makes them transmit vibration energy from one particle to the next quickly. An echo is a sound wave and sound waves are longitudinal waves that occur by the collision of particles to move the vibrations along, and this is why they move slower in air.
Answer: True
Explanation:
The federal government possesses only those powers delegated to it by the Constitution. While the state and the people have the remaining power.
This was necessary, so the state and the people could have freedom of right and address some decisions which doesn't seat well with them when proposed by the Federal government.
Answer: Wendy did not use random assignment
Explanation: Wendy's failure to randomly assign participants or subject to his research will pose a threat to the internal validity of his study. The internal validity of a study simply refers to the structure of an experiment and it's trustworthiness in establishing causal relationship between the applied treatment used a study and the observed outcome. Wendy's decision to ignore random assignment and opt for a manual assignment of subject to each treatment will pose a threat to the structure of his study and hence the establishment of a causal relationship between the treatment t and outcome of the study.
Cahokia is a known historic site that can be found in Illinois, United States. Tribes lived in this place during the 17th century and they became the most influential urban community during this time. Mound Builders was also known as Cahokia tribe, they move to other place and decline to stay due to weather condition and tribal warfare. They started moving in different regions.
Because the Ohio River Valley was a great spot for farming (it had very fertile land), and there was and abundance of beavers, and their fur was very valuable. The British wanted this land for the profits, and so did the French, leading to the French and Indian War.
