Using the concept that :
<span>The skin cell has twice the number of chromosomes as the sperm cell has.
</span>Hence,
<span>The sperm cell has 39 chromosomes.
The skin Cell will have = 39 x 2
= 78 </span><span>chromosomes.</span>
The correct answer is d: cDNA.
<span>cDNA or complementary DNA is DNA synthesized usually from messenger RNA (mRNA) by the enzyme reverse transcriptase. Because this molecule is from mRNA it contains only exons. cDNA is also produced naturally by retroviruses, for example, HIV virus.</span>
E, D, and C I believe. It has been a while since I took this class.
Sound waves<span> coming from farther above, where it is warmer, will experience a refraction. The change in speed from the warmer </span>air<span> to the cooler </span>air<span> causes a bending effect, as the </span>sound travels<span> downward.</span>
Water, Humus, air, plants, organisms , nutrients, particles (inorganic
