Dna replication
a. begins when two dna molecules join together to exchange segments
b. occurs in the endoplasmic reticulum results in the formation of four new dna strands
c. occurs through the addition of nucleotides to the end of the parental dna molecule
d. uses each strand of a dna molecule as a template for the creation of a new strand

The correct answer will be option D.

Explanation:

DNA replication is a complex process which forms the exact copy of the DNA molecule from the existing DNA.  This process takes place during the synthesis phase or S-phase of the cell cycle which takes place in the cytosol of prokaryotes and nucleus of the eukaryotes.

The most common way of producing replicas of the DNA molecule is through semi-conservative mode in which each strand of DNA is synthesized from both the strands of the parental DNA using as a template.

Thus, option D is the correct answer.

answer: - few nutrients

high pressure

low temperatures

explanation: 1. few nutrients:   open-ocean zone is located way far from the land, which is the main source of the essential nutrients.2. high pressure: pressure increases by 1 atmosphere for every 10 meters increase in depth.3. ample sunlight: a large fraction of the sunlight is reflected back to the atmosphere from the sea surface. 4. varying salinity: below the thermocline, the water is isolated from the atmosphere so the salinity remains stable over the year.5. low temperatures:   the temperature of open-ocean zone ranges from a low of -2°c to an average of 17°c

both anaerobic and aerobic respiration use glucose (or other carbohydrates), proteins and lipids to produce atp and nadh. cell uses those energy molecules, obtained from food and   breaks them down during the chemical reactions of respiration. in anaerobic respiration, nadh is regenerated to nad+ by enzymes lactate dehydrogenase (lactate is produced, e.g. in muscle cells) or by alcohol dehydrogenase where ethanol is produced (alcohol fermentation), while in aerobic respiration, electrons from nadh are deposited in the mitochondria to regenerate nad+ (electron transport chain. anaerobic respiration produces 2 atp per molecule of glucose compared to aerobic respiration where about 38 atp molecules are produced.