I think it is the 3rd one because health problems at older age.
Exchange of gases in fish is very efficient because of: the large surface area of the gills. the large surface area of the blood capillaries in each gill filament. the short distance required for diffusion – the outer layer of the gill filaments and the capillary walls are just one cell thick.
B is correct. Krypton is a noble gas which has a full outer shell of 8 electrons and is generally unreactive because of it.
<span>The juxtaglomerular apparatus is a structure (formed by the distal convoluted tubule and the glomerular afferent arteriole) with the function in the regulation of blood pressure and the filtration rate of the glomerulus. Its primary components are:
</span> <span><span>· </span>the macula densa- specialized epithelial cells in the distal convoluted tubule (detect Na concentration),
</span> <span><span>· </span>juxtaglomerular cells- formed from the smooth muscle cells of the afferent arteriole (secrete renin),</span>
<span><span>· </span>extraglomerular mesangial cells (lacis cells)-unknown function.</span> <span> </span>
