Put the steps of binary fission in order from first (1) to last (4).
dna molecules attach to the cell membrane.
two new, identical cells are produced
dna is copied
the membrane elongates and pinches off

answer; i believe that the correct answer is(d) nondisjunction during meiosis;

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.

the answer would be..

b. sucking

the tricuspid valve is present between right atrium and right ventricle