What is the name of the organ, shown here, that makes the "lub-dub" sound in your chest?

Apaleontologist finds a plant fossil that shows that the plant had seeds. what can the paleontologist conclude?

Producing disposable grocery bags consumes resources. recycling disposable bags is a solution that can recover some of the resources used to make new bags. which of the following behaviors could further refine the solution? a. disposing of bags by burning them b. reusing bags whenever possible c. using bags at once so that they do not break d. using only nonrenewable materials to make new bags subject is environmental science for apex users

What kinds of molecules can pass through the cell membrane without any problem?