Plants are divided into either vascular or nonvascular groups. These two groups share some characteristics, such as cell walls, but there are several important differences in their structures. Nonvascular plants lack which of the following structures? true roots, chloroplasts, and stems
true roots, phloem, and xylem.
true roots, xylem, and cell walls
true roots, cell membranes, and flowers

Leaves specifically the gas exchange between plants and the environment. while plants undergo photosynthesis, they also partake in cellular respiration. respiration is the process that happens in the leaves of plants.

Mars and earth have quite a few things in common. both are  terrestrial planets, both are located within the sun’s  habitable zone, both have  polar ice caps, similarly  tilted axes, and similar  variations in temperature. and according to some of the latest scientific data obtained by rovers and atmospheric probes, it is now known that mars once had a  dense atmosphere  and was covered with  warm, flowing water.

Sorry  i don't understand can you rephrase that