First of all, please note that this is a question whose answer is in something of a state of flux. As can be seen in the link below, some of the conventional wisdom about Jamestown’s problems is being called into question by recent archaeological finds.
The conventional wisdom holds that Jamestown’s problems began when the colonists chose a bad site for their settlement. They chose a place that would be easy to defend against Indians, not realizing that it was in the middle of a swamp full of mosquitoes that carried malaria. This led to the death of many Jamestown settlers. Jamestown also encountered problems, according to conventional wisdom, because the settlers arrived too late in the year and without enough people who could get a colony started. They arrived too late to plant and too many of their people were either gentlemen or servants who waited on the gentlemen, not carpenters and farmers. Some of the settlement’s problems are also attributed to aggressive actions against the Native Americans who had been willing to trade with the settlers at first. The settlers’ attempts to take the Indians’ supplies caused trade to be cut off and also led to attacks on settlers. These are the factors that are generally cited in textbooks as having caused Jamestown’s problems. It is likely that these are the answers that your teacher wants to see.
Like any new endeavor, cooperation is required. Have you ever worked on a project with a group of classmates? I bet you have had some that work hard, some that work a little, and some that do nothing. That was happening in Jamestown. Under the extreme conditions, this caused a lot of strife. Put yourself in their position and imagine life in an untamed world.
Captain John Smith took control of the colony. He made a rule, if you don't work, you don't eat. This helped create a more fair society. It is helpful when looking at history, to remember that human nature contributes to any situation. Try to identify a situation in your life that gives you some understanding of how the settlers felt. Through this lense, you will have a better understanding of history.