How many strands does a dna molecule have?

Assume that a student is given two different models of bacteria, with one model consisting of big bacteria and the other consisting of small bacteria. how can the student demonstate the theory of endosymbiosis using the models

In iceland, the mid atlantic ridge runs through the center of the contry. what can you conclude about the apperence of iceland many thousands of years from now?

If the dimensions of a cube-shaped cell with a length,height, and width of 1 micrometer were to double, what would be the cell's new ratio of surface area to volume? a.3 to 1 b.4 to 3 c.1 to 2 d1 to 6