For this question the answer will be D.
Answer:
B. They form cell membranes
Explanation:
There's not really an explanation, that's just a fact. A phospholipid bilayer has two layers of, yep, phospholipids. They stay together well and kind of move around a little, allowing small particles to pass through. There are some proteins in them also that help them function as cell membranes.
Answer:
Steam-powered trains.
Explanation: Railroads provided the most dramatic transportation growth during the 1800s. They facilitated the movement of people, goods, and information, decreased shipping costs and time, and strengthened the links between the Old Northwest and the East.
Answer:
1. strikes
2. low wages
3. unsafe working conditions
4. social classes
5. ways to teach others trades
Explanation: