Diatoms have a cell wall made of two halves called
valves.
nuclei.
thylakoids.
none of the above

The graph shows the solubility of several different salts in water, across a range of temperatures. according to the graph, which salt can dissolve at a concentration of about 60 g/100 cm3 of water at 40 degrees celsius?

The leopard frog and the pickerel frog are two closely related species. in areas where their ranges overlap, the frogs will remain separate species if they

The finches on the galapagos island were similar in form except for variations of their beaks. darwin observed that these variations were useful for: attracting a mate defending territory building nests gathering food