★ Biology Quiz
the backflow of blood stops in veins by …….
A. valves
B. muscles
C. heartbeats
D. lymphatic vessels
Select your answer:
Topics:
Tutor Oral Biology Anatomy Respiratory System Cardiology Digestion and Microbes Genetics and Censorship Specialties: Neurological and Geriatric Cell Structure and Function Concept Diseases & Disorders Regulation of Heart Rate Digestive System (Gastroenterology) Perioperative Nursing Care Diseases Key Terms Homeostasis and Disease Coronary Heart Diseases Urinary SystemOther quiz:
Homeostasis, Nutrition, Digestion & Absorption › ViewWhat is an ectotherm?
A. fish
B. cat
C. dog
D. human
Cell › View
Protein Factory of cell
A. Nucleus
B. Ribosome
C. Mitochondria
D. ER