This is B; false.
Europe is not located in the tropics. In fact, no European countries lie in the tropical region. Europe is located in the temperate climate zone.
I believe the example of an environmental variation in the above question is, A. Marge dyes her hair blue. Variation represents any difference between cells, individual organisms, or groups of organisms of any species caused by either genetic differences or by the effect of environmental factors. Environmental variation is the ability of an organism to alter its phenotype depending on environmental conditions.
2 and 3 are too similar to distinguish because they both are saying it's been back up on several different accounts but 3 seems like a more solid answer go with 3
Myofibrils are the building blocks or contractile unit of each muscle fiber. The tiniest functional unit of skeletal muscle, the sarcomere, is found in the myofibrils and is made up of protein filaments: actin (thin) and myosin (thick).
