An atlantic crossing by boat from england to new england took 60–80 days in the 18th century. in the late 19th century the voyage took less than a week. how do you think these time differences for travel might have impacted the spread of infectious diseases from europe to the americas, or vice versa?

The phlogiston theory in the 17th century attempted to explain burning. the theory stated that combustable objects contained a material called phlogiston, a substance without mass, color, odor, etc. after objects burned, the objects were dephlogistonated and were then in their true form. the phlogiston theory was accepted until the 18th century, when lavoisier proved that combustion requires a gas that has mass. phlogiston is considered a) to be scientific knowledge b) not to be scientific knowledge c) to be proven by scientific method d) to be accepted in the modern scientific community

What are the four basic classes of organic molecules how do they differ structurally and functionally

Talking listening and reacting non verbally are all part of communicating