Which is more useful to biologists studying ancestry homologous structures or analogous structures?

Which technically is nasa developing that will astronauts reach mars

Which description provides the best objective summary of the article in the passage?

When new rock is added to an oceanic ridge, the magnetized strips on either side of the ridge are evidence of sea-floor spreading. this is because the rocks on the two sides of the ridge o are equal in width and in polarity are polar opposites oare magnetized vary in width but are equal in polarity