Active muscles demand huge amounts of oxygen, and the circulatory system works hard to provide it. Blood carries oxygen to the muscles. When the body is at rest, blood carries nutrients to the muscles so that they can repair and rebuild themselves. Blood also carries away the waste products that hard-working muscles produce, back out through the lungs to be filtered.
so they Circulatory system xx muscular system :)
The net force is the vector sum of all the forces that act upon an object. That is to say, the net force is the sum of all the forces,
The answer is C.
Transgenic means that one or more DNA sequences from another species has been introduced by artificial means. For example, animals usually are made transgenic by having a small sequence of DNA injected into a fertilized egg or developing embryo. Transgenic plants can be made by introducing foreign DNA into a variety of different tissues.
Most transgenic organisms are generated in the laboratory for research purposes. Others have been developed for commercial purposes such as golden rice that has been modified to produce beta-carotene, the precursor to vitamin A.