Complex biomorphs appear on a Nakhla chip shown in this scanning electron microscope (SEM) frame. This image contains three basic forms: Broad smooth knife-shaped features, elongated features with rounded endcaps and transverse compartments or dividers, and donut-shaped small features, each about 1 micrometer in diameter. One possibility is the donut-shaped features are derived from the compartments present in the elongated features.
Photo Credit: NASA/David McKay