some blood vessels carry blood away from the heart to the different parts of the body these blood vessels are called__________.
•arteries
•veins
•capillaries
•none of these
the adult heart beats about ____ times every minute.
• 70
•80
•90
•40
the number of heart beat per minute is called the_____________.
•heart failure
•transportation
•heart rate
•both a and b
Answers
Answer:
Arteiries
80
hear rate
Answer:
Explanation:
Living things must be capable of transporting nutrients, wastes and gases to and from cells. Single-celled organisms use their cell surface as a point of exchange with the outside environment. Multicellular organisms have developed transport and circulatory systems to deliver oxygen and food to cells and remove carbon dioxide and metabolic wastes. Sponges are the simplest animals, yet even they have a transport system. Seawater is the medium of transport and is propelled in and out of the sponge by ciliary action. Simple animals, such as the hydra and planaria (shown in Figure 1), lack specialized organs such as hearts and blood vessels, instead using their skin as an exchange point for materials. This, however, limits the size an animal can attain. To become larger, they need specialized organs and organ systems.
Multicellular animals do not have most of their cells in contact with the external environment and so have developed circulatory systems to transport nutrients, oxygen, carbon dioxide and metabolic wastes. Components of the circulatory system include
blood: a connective tissue of liquid plasma and cells
heart: a muscular pump to move the blood
blood vessels: arteries, capillaries and veins that deliver blood to all tissues
