Answer:
they could help the plants grow and animals
Explanation:
Im pretty sure its Harlem. sorry if wronf
Answer:
The study of ancient bones gives us information about our human ancestors and they are important to us it shows what type of stuff lived before us and it may seem boring but it really isn't its nice
Explanation:
*Railroad
Because its faster and cheaper
*coal
Because Electricity didn't exist until the 19th or 20th century I think
*Assembly line
* Slave trade
Because the slave trade existed long before that