In connective tissue, what is the unbranched, triple helical fiber that gives strength to tendons and ligaments? It is also a big part of why barbecue tastes so good.

What is the first organ system to reach functional state?

In which week will the atrioventricular valve cusps form?

The distal left ____ arch forms the ductus arteriosus. 

In the 4th week, the _____________ is positioned at the top of the primitive atrium.

Click the area of the sinus venosus. 

Actin filaments, which are essential in muscle contraction, are an example of what type of cytoskeletal filament?

The ___________ forms the right ventricle.

In fetal circulation, what connects the pulmonary artery to the aorta?

By birth, the normal heart rate is ___________ beats per minute.