A school physician performed an experiment to investigate the effects of aerobic exercise on high school freshmen. He examined 25 student volunteers and found them to be in good health. He then had the students perform aerobic
exercises, such as jogging, swimming, and bicycling. The doctor recorded the students' pulse rates before each activity,
during each activity, and after each activity. Which is the independent variable in this experiment?

answer

crater lake was formed when mount mazama produced a large eruption and collapsed to form a caldera, which then filled with water forming a lake.

1: most common garden plants prefer loam — soils with a balance of different-sized mineral particles (approximately 40% sand, 40% silt, and 20% clay) with ample organic matter and pore space. however, some plants grow better in sandy soils, while others are well-adapted to clay soils.

2: available water capacity is the maximum amount of plant available water a soil can provide. it is an indicator of a soil's ability to retain water and make it sufficiently available for plant use. available water capacity is the water held in soil between its field capacity and permanent wilting point.

3: it is the same for all living things (plants and animals). it also includes very tiny organisms that our eyes cannot see. they are known as microorganisms, and include viruses, bacteria and fungi.

blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart. as the ventricle contracts, blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs where it is oxygenated.