Are there any animals that can live underwater and live on land? i'm not talking about animals that can breathe a long time underwater but animals that can stay on land as long as they want and stay underwater as long as they want.

hmm.. Animals that can survive in land and aquatic environments typically still have a preferred habitat. For example alligators are primarily found in water but they also spend time on land and can hunt on land. Amphibians (ex. tadpoles to frogs) usually begin their lives in water but develop terrestrial adaptations as they grow. Amphibians may be semiaquatic and comfortably switch from land to water terrains. The European pond turtle can live on both land and water. Hopefully this answered your question :)

Explanation:

the answer is; comparing the frequency of collisions with and without the device

this makes the anti-collision system an independent variable and the collisions a dependent variable. if there are fewer collisions with an anti-collision system that without, then it can be stated that the system is a success. essentially, collisions under an anti-collision system are compared with the frequency of collisions by cars with the human drivers.

the answer is d. chordata