In the disease osteoporosis there is a significant loss of spongy bone. explain how the loss of this specific bone material can weaken a bone.

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

Asap indicate the coat color and the proportion of offspring with that color for each of the following crosses of rabbits. assume all are homozygous. alleles: a=agouti, c=chinchilla, a=albino, a is dominant over c and a, c is dominant over a agouti x chinchilla a) 1/2 chinchilla, 1/2 agouti b) 3/4 chinchilla, 1/4 agouti c) all agouti

The greenhouse effect a. something that has occurred for millions of years b. an unnatural phenomenon caused by humans that maintains earths temperature range. c. the results of the differences in the angle of the suns rays d. an unnatural phenomenon that causes heat energy to be radiated back into the atmosphere