Which of the following choices describes the correct order of events that occur during the cardiac cycle: i. The mitral and tricuspid valves open and the atria force blood into the ventricles. ii. The ventricles contract and push the blood out. iii. The heart relaxes in diastole and the atria fill with blood. iv. The ventricles fill with blood

thrombocytopenia, which is a deficiency in blood platelets, can cause bleeding and bruising in the dermis similar to senile purpura. other possible causes include: exposure to ultraviolet rays and aging skin are common causes of senile purpura. senile purpura may also be a sign of collagen loss in the skin and bones.

which

what is a measurement of the earth’s history divided into time periods?

> fossil record <

sedimentary rock

> geologic time scale <

radioactive elements

d. planting trees

the trees take in carbon to make oxygen.