Tree bark is
made of living xylem cells
a layer of dead dermal tissue
only found in older plants
made of flexible collenchyma cells

In the diagram below, the northern hemisphere would be in what season at position a a.fall b. winter c.summer d.spring

If a strand of dna has 35% thymine. what is the percentage of cytosine, adenine, guanine?

According to theories of how life began, how did early organic molecules begin to separate from the outside world? a: specialized enzymes were required b: chains of amino acids created a barrier c: formation of microspheres or vesicles d: rna catalyzed the formation of membranes