Explain in detail the processes leading to biological nitrogen fixation. Ensure you outline how the symbiotic relationship between the bacteria and the plant is developed, the genes involved and the function of different enzymes

Match the following terms describing electrical events with the correct phases of the cardiac cycle. the ventricular muscle cells depolarize at the start of this phase. during this phase, na+ entry through the funny channels causes the pacemaker potential of sa nodal cells to gradually become less negative until it reaches threshold. the ventricular muscle cells repolarize right before this phase. the cytosolic concentration of calcium in the contractile cells of the ventricle is highest during this phase. a. isovolumetric relaxation b. ventricular ejection c. isovolumetric contraction d. ventricular filling

The leopard frog and the pickerel frog are two closely related species. in areas where their ranges overlap, the frogs will remain separate species if they

Identify the terms using the following picture. principle of dominance item 1 can be described as the . item 2 can be described as the . the "p" represents from one parent.