I think the correct answer would be the first option. The best method to use in order to measure the distance of star would be to calculate the variations in the position of the star due to movement of Earth in its orbit. The doppler shift which is what is being described in the last three options does not calculate the distance rather it calculates the relative velocity. The method used in measuring the distance was introduced by Edwin Hubble where he found that relative velocity of a body in space is directly proportional to the distance of that body from Earth.
Answer: A.
Explanation: Hope this helps
Answer:
<h2>
Through production of news cell-surface proteins with a different molecular structure by each new generation. Letter B</h2>
Explanation:
The life cycle of theses paratises extracellular alternate between the salivary glands of the insect transmitter and the blood of the mammal. During the set prior to the entry into the host, the metacylic parasites express a dense over formed by the Variant Surface of Glycoprotein, after entering to the mammal host they transform into a morphology that stays in the bloodstream.
<em>The parasites have to manipulate hosts cells in order to avoid the production of antimicrobial molecules and to benefit from growth factor production.</em>
<em>Intracellular protozoa have a remarkable adaptive capacity as they are able to resist killing by remodelling the phagosomal compartments where they reside and by interfering with the signalling pathway that leads to cellular activation. </em>
