Read the passage.
around the mid-17th century, robert hooke observed part of a cork tree with a simple microscope. he realized that the cork consisted of small, box-like parts. he called these box-like parts cells. in the late 17th century, one-celled organisms were first observed with a microscope. until that time, nobody knew that microscopic life forms existed.
in the 19th century, improved microscopes and processes were used. this led to the discovery that animal tissues were also made of cells. in addition, 19th-century scientists observed how new cells formed. they realized that cells always form from cells that already exist. scientists also discovered that living cells could carry out certain chemical reactions.
which option correctly explains how the cell theory was formed?
a) scientists formed the cell theory in the 17th century but stopped using it until new discoveries were made in the 19th century.
b)scientists’ understanding of cells continually improved as the results of studies built upon each other over time and formed the cell theory.
c)once the original facts were discovered, the only part of the cell theory that could change was its structure.
d)scientists discovered cells in the 17th century and created the cell theory in the exact form in which it is seen today.

Part 1: a magnetic levitation or maglev train rides rails without touching them. explain how this works using your data. include the appropriate magnet drawing in your answer. part 2: two objects are near a bar magnet. one is about 1 cm away, while the other is 6 cm away. compare and contrast the magnetic force that affects each object. use your data to answer the question

Red’s momentum vector before the collision is green’s momentum vector after the collision. question 1 options: equal to shorter than longer than question 2 (1 point) saved since green bounces off red, this must be an collision. question 2 options: explosion elastic inelastic question 3 (1 point) red transfers of its momentum to green during the collision. question 3 options: none all little most question 4 (4 points) why does red transfer all its momentum to green? back up your answer with information from the simulation. write at least 2 sentences. question 4 options: skip toolbars for . more insert actions. more text actions. more paragraph style actions. question 5 (1 point) now make red much heavier than green. answer the questions below to describe how both red and green behave after the collision. question 5 options: slowed down sped up kept the same velocity question 6 (1 point) green sped up during the collision as it question 6 options: gained momentum from red lost momentum to red maintained a constant momentum. question 7 (1 point) after the collision . . question 7 options: both green and red moved to the right. both green and red stopped as they have lost all momentum. red stopped and green moved to the right. red bounced off green and went to the left. green moved to the right. question 8 (4 points) only some of red’s momentum was transferred to green. why did this occur? back up your answer with information from the simulation. write at least 2 sentences. question 8 options: skip toolbars for . more insert actions. more text actions. more paragraph style actions. question 9 (1 point) now make red much lighter than green. answer the questions below to describe how both red and green behave after the collision question 9 options: green sped up after the collision therefore it must have gained momentum. green sped up after the collision therefore it must have lost momentum. green slowed down after the collision therefore it must have gained momentum. green slowed down after the collision therefore it must have lost momentum. question 10 (1 point) since green gained momentum, red had to have momentum because you cannot create or destroy momentum. question 10 options: gained lost kept the same amount of question 11 (1 point) since green was so much and harder to move, it caused red to bounce back to the left giving red . question 11 options: heavier . . . . positive lighter. . . . negative lighter. . . . positive heavier . . . . negative question 12 (4 points) now, click on more data at the bottom of the sim. play with different numbers for the masses and starting velocities. you can even make the starting velocities negative! tell me one thing you discovered by adjusting the speeds and masses. write at least 2 sentences. be specific and use words like velocity, momentum, mass, increased, decreased, etc. 13. true or false: when red and green collide, they stick together. question 13 options: true false question 14 (1 point) the velocity of red & green after the collision is the velocity that red started off with. question 14 options: larger than smaller than equal to question 15 (1 point) the velocity after the collision was less because the mass has question 15 options: stayed the same decreased increased question 16 (1 point) the momentum before the collision was the momentum after the collision. question 16 options: larger than smaller than equal to conclusions question 17 (4 points) how are elastic and inelastic collisions different? give two or more ways. your answer should have at least 2 sentences. question 18 (4 points) give an example of a collision in real life. use the law of conservation of energy to describe the transfer of momentum. be sure and discuss the momentum before and after the collision occurs. you will need at least 3 sentences to thoroughly answer this question.

Which is special about a dc circuit ? a. it has both series and parallel components b. it has only series or only parallel components c. charge moves in a single direction d. charge moves back and forth quickly