Question

31 contractions of these can help the hair-like projections move a developing embryo along the fallopian tubes

Explanation:

The question refers to structures whose contractions assist cilia (hair-like projections) in moving an embryo through the fallopian tubes. Smooth muscle tissue lines the fallopian tubes, and its peristaltic contractions work alongside cilia to propel the developing embryo toward the uterus.

Answer:

Smooth muscles (or fallopian tube smooth muscle)