How is a tissue different from an organ? how are they similar?

What is thought to have caused the mass extinction at the end of the cretaceous period?

2. which of the following statements does not accurately describe stem cells? a. embryonic stem cells make up the inner cell mass of a blastocyst. b. with more research, stem cells may be used to repair or replace damaged cells. c. the use of stem cells is without any objections since it can be used in therapies to humans. d. adult stem cells are multipotent and can differentiate into many types of cells.

Pulmonary arteries carry highly oxygenated blood. true or false?