A barrel cactus would do best in a desert environment. It has adapted to go long periods without water and can store the water it collects within its stem. It would not do well in a rainforest or swamp because they are too wet, and plants can get too much water. A tundra is icy and frozen and does not support plant life year-round.

The desert is made entirely of sand. It rarely rains and is very dry. There are only a few plants, and they have small leaves. The sand is scorching and moves every time it is touched; when the wind blows, the sand shifts in all directions. Organisms that live in this type of habitat and survive well must be adapted to these conditions. A saguaro cactus, camel, scorpion, and lizard are all organisms that have variations in their behaviors and physical traits that allow them to survive in such a harsh environment.

The best argument for why some organisms don't survive as well as others in a habitat is Natalie's. The reasoning she gave was clear and correct. If animals don't have the right traits for that particular environment, they will not survive as well. If something changes in their habitat and they don't adapt quickly, they may not survive as well as another plant or animal.

Within each habitat, there is a balance that allows its members to thrive and survive. If one member is removed, it throws off that balance and affects the food chain and other organism's survival chances. Other organisms may not survive as well if one member is removed. If bamboo is removed from a forest where panda lives, then the panda is at risk for starvation because bamboo is their primary food source. One simple change can cause a ripple effect with other organisms.

The grasslands are not the barrel cactus' natural habitat, so it does not have all of the features or characteristics that would make an ideal habitat. It does have plenty of sun, occasional rain, and open areas to grow, which would work well for a cactus. The cactus may not grow as well as it would in the desert and may need to adapt to the new environment to survive.

An alligator would be able to survive in a tropical rainforest with large lakes and ponds better than any of the other choices. It may not survive as well in this habitat when you compare it to the swampy areas they thrive in, but it would have all of its basic needs met.

The osprey would be able to survive in a swamp but maybe not as well as in its natural habitat. The wetland has other predators that hunt similar food sources and make nests where the ospreys would so it would have to compete for these basic needs to be fulfilled. Ospreys also have large open bodies of water for hunting, and many swamps have thick canopies from the trees. An osprey can survive in a swamp, but it would not do as well as native birds.

Within each habitat, there is a balance that allows its members to thrive and survive. Organisms depend on one another for survival. If there were no prey for predators in a habitat, they would die out, be forced to relocate, or have to adapt to the new changes. Some organisms survive better in habitats than others, and it is dependent on their ability to adapt to their changing surroundings.

Northern states are known to have cold winter, and in many areas they experience long periods with freezing temperatures and frozen water. Alligators cannot survive in the winter months in a Northern state. The alligator may be fine during the warmer seasons but would not survive all year. Many alligators are moving further north in the United States, but they are still not able to reach the upper Northern states due to the cold winters.

The best argument for what would happen to panda bears if moved to the desert is Rachel's argument. The reasoning she gave was clear and correct. If animals don't have the right traits for that particular environment, they will not survive as well. If something changes in their habitat and they don't adapt quickly, they may not survive as well as another plant or animal.