Which of the following is a flap of tissue in the heart that prevents blood from flowing backwards? a: atrium b: pacemaker c: septum d: valve

Select the correct answer. which formula describes newton’s second law of motion? a. force=mass x accerlaration b. mass/accerlaration c. mass x volacity d. mass/ volacity

Creating new things to solve problems and improve life depends on the close interaction of which two fields?

Which is an example of a vestigial structure? a: paw of a lionb: wing of a birdc: appendix of a humand: tail of a cat(i think it's a but i'm not sure)