Gastrulation produces an oval, three-layered sheet known as the          

Compared to arteries, veins      

The secretion of the seminal vesicles contains ________, which forms a temporary semen clot within the vagina after ejaculation.  

Contractions of the papillary muscles  

Identify number 5.  

What structure covers the trachea during swallowing?

The physical maturation of sperm is called  

One of the key steps of protein synthesis is transcription. What happens during transcription?

 Identify number 4.  

Name the artery labeled 1?