During the phase of the cardiac cycle called , the entire heart is relaxed and blood flows into all four chambers. 2. during the phase of the cardiac cycle called , the heart contracts beginning with the atria and then the ventricles. 3. when the ventricles contract, the snap closed. 4. a defective heart valve can be identified by the sound of a(n) . 5. the , or pacemaker, initiates the heartbeat by generating electrical impulses that spread across both atria. 6. impulses are delayed briefly at the and are then transmitted through special fibers to the base of the ventricles. strong contractions begin at the apex of the heart and drive blood up and out of the heart. 7. a(n) records the electrical changes that occur during the heartbeat and provides data on the health of the heart.

1. The right answer is Diastole.

The diastole is the period during which the heart relaxes after contracting. We talk about ventricular diastole when the ventricles relax, and atrial or atrial diastole when the atria relax. At rest, the diastole time of the heart is about 0.49 seconds.

2. The right answer is Systole.

Systole is the contraction phase of the heart, where the blood is expelled to the cardiovascular system.

The pressure during systole is the highest number the doctor indicates when measuring blood pressure.

During systole, the cardiac ventricles, filled during diastole, contract. The systole has three phases and lasts about 0.27 seconds.

3. The right answer is atrioventricular valves.

There are two valves that separate the ventricles of the atria. They are called atrioventricular valves. On the right side is the tricuspid valve, and on the left side is the mitral valve.

Each of these valves is composed of a fibrous ring of the cardiac skeleton, leaflets, ropes and muscle pillars found in their respective ventricles.

4. The right answer is heart murmur.

Heart murmurs or heart murmurs are characterized by "unusual" noises heard during a stethoscope auscultation during the heartbeat. They are produced by turbulence of the blood flow to the heart and can be caused by various pathologies.

Heart murmurs may be congenital, that is, present at birth, or may develop later in life. All may be concerned: children, adolescents, adults and the elderly.

5. The right answer is sinoatrial node.

The sinoatrial node is a small knot of barely visible tissue located on the posterior wall of the right atrium. This tiny region controls all the regulation mechanism of the heartbeat. The pulses start normally in the sino-atrial node. This generates a brief, low-intensity electric pulse, approximately 72 times per minute, in an adult at rest. From there, the impulse propagates along the tissue blades that form the two atria, exciting the muscle fibers in its path, which causes the contraction of the atria and the passage of the blood they contain in the empty ventricles.

6. The right answer is atrioventricular node.

The atrioventricular or atrioventricular (or Aschoff-Tawara) node is a heart structure made of cardionector tissue. It transmits the muscular contraction impulse between the atria and the ventricles via the bundle of His.

The atrioventricular node is located in the atrioventricular septum at the Koch Triangle, a structure visible in the right atrium and delimited by the septal valve of the tricuspid valve, the coronary sinus and the Todaro tendon. It is in continuity with the bundle of His at the level of the central fibrous body of the heart. It is most often vascularized by a branch of the right coronary artery.

7. The right answer is electrocardiogram.

An electrocardiogram or ECG is a medical examination in cardiology to record heart activity. It is based on the measurement of electrical currents passing through the organ at each of its contractions.  With the ECG, a doctor can determine whether the electrical activity thus observed is normal or irregular.

c. genetic engineering

explanation:

answer: decrease

a limiting factor is the one which decrease the abundance, distribution and causes extinction of the population of species in a ecosystem. here, predators including hawks, owls and snakes are the limiting factor for the population of mexican free tailed bat.   although bats are nocturnal animals as they forge for food at night these predators also may remain active during night which can decrease the population of the mexican free-tailed bats. also, these bats eat only one type of insects that are moths. the food can also be a limiting factor as all 400 members are dependent upon same type of food needs that are moths. the decrease in the moth population can cause decrease in population size of the mexican free-tailed bats.

therefore, the scenarios will most likely to decrease the population size of the mexican free-tailed bats.