Answer:
to add nucleotides to a DNA primer
Explanation:
The Polymerase Chain Reaction (PCR) is a technique widely used in molecular biology in order to amplify small segments of DNA (100 to 1000 bases). PCR uses a thermostable DNA Taq polymerase that adds nucleotides to the DNA template at the position specified by short single-stranded DNA primers that bind to this template by complementary base pairing during the annealing phase of the PCR cycle. Subsequently, the DNA polymerase adds deoxynucleotide triphosphates (dNTPs) to the opposite DNA strand, this phase of the PCR cycle is known as the elongation phase. Finally, the resulting double-stranded DNA fragment is separated by heat during the denaturation step and this 3-step PCR cycle is repeated many times to amplify the target DNA region.
In positive feedback, rising levels of hormones feedback to increase hormone production. During most of the menstrual cycle, estrogen and progesterone provide negative feedback to the hypothalamus and pituitary gland. This keeps their levels more or less constant.
In negative feedback, rising levels of hormones feedback to the hypothalamus and pituitary gland to decrease the production of the hormones. In positive feedback, rising levels of hormones feedback to increase hormone production. During most of the menstrual cycle, estrogen and progesterone provide negative feedback to the hypothalamus and pituitary gland. This keeps their levels more or less constant. During days 12–14, however, estrogen provides positive feedback to the hypothalamus and pituitary gland. This causes a rapid rise in the production of estrogen by the ovaries and leads to ovulation.
Answer:
Biotic factors are those that are living, which includes all of the plants, animals, fungi, protists and bacteria that make their homes there. Abiotic factors are those that are non-living, and these include temperature, pressure, wind, sunlight and weather systems.
Because of the nitrogen cycle all of the above answers are correct
