Pathologists take blood from the heart to check for bacteria in the blood

yes. If a person should suffer a severe infection of the blood, via osteomyolytis or other infection, the Heart is one place bacteria may successfully hide. If a patient is quite ill or may be ill, a line (tube) will be placed in their heart via the blood vessels of their arm so that antibiotics can be pumped directly into the heart, sometimes for many weeks.

answer:

the water molecules are transferred from the roots to the stem or top parts of the tall tree because of important properties of water which are adhesion, cohesion and capillary action. cohesion is the property of water molecules keeps water molecules in a combined state by sharing of bonds between them at the atomic level. adhesion allows the interaction of water molecules with other substances or substrate. adhesion will cause the attachment of water molecules to the wall of the vessel (xylem) of the plant. capillary action occurs when the adhesive force to the vessel wall is stronger than the cohesive force between water molecules. capillary action mimics the transfer of water from a tube or pipe. in this way water utilizes its property to transfer water from down to top level of the plant.  

well first you need the sample of the temperature and gas level. i couldnt write a hypothesis unless i had some data. i think temperature changes will effect volumes of gas because gas changed into a solid or liquid at specific temperatures.