Cortex is the stores the food and water for roots
Model two because it includes more organelles
After holding the weight for so long, the muscle would get tired, in an effort to tell the brain to stop holding the weight because the muscle fibers cannot handle it any more. Lactic acid is a by-product during muscle contraction that leads to the pain.
Answer:
Physical changes can easily be reversed but chemical changes cannot because in physical change only state is changed while in chemical change, new substances are formed. For example, when water in liquid form is condensed, it changes into solid form (ice). It is a physical change because water in liquid and solid have the same chemical formula only arrangement of molecules are different. Burning of wood is a chemical change because new substances i. e. carbondioxide and heat is produced.
C- putting organisms into categories based on similar characteristics.
