The pulmonary vein carries oxygenated blood from the lungs to the left atrium
The correct answer is (a.) Its spindle-shaped cells allow it to do smooth muscles. The structure of the cardiac muscles which is spindle-shaped is very important for the heart to withstand the stretching of the muscles during the contractions. Also for its smooth surface which is very important to prevent any possible blood clot during circulation.
There are several reasons that contribute to the high level of biodiversity found in the wetlands. Firstly it provides numerous animals and insects to find their food and breed easily. Also this wetland helps the animals to camouflage against their enemies. The wetlands provide home for abundance of marine animals. It is actually a place that maintains a natural balance.<span />
DNA or deoxyribonucleic acid is macromolecule composed of nucleotides (nitrogen nucleobase, deoxyribose sugar and phosphate group) which carries genetic information (instructions). Instructions within DNA are for development, growth, reproduction and many other functional roles of an organism.
All of the cells within an organism contain the same genome (full set of DNA-chromosomes). When cells begin the process of differentiation (cells become specified) their genome stays the same, but the gene expression is different (different genes are on or off).
