Use the correct form of the verb ser or estar:
él maestro.

when entering your answers for fill in the blank and essay questions, be sure to use accent marks and/or correct punctuation to avoid your answer being marked incorrect.

you may copy and paste the accented character or punctuation mark from this list if needed:
á é í ó ú ñ á é í ó ú ¿ ¡

answer for blank 1:

they need to keep water moving over their gills so they seem to have active periods and restful periods instead of undergoing deep  sleep.  they sleep swim

explanation:

nosotros = we   .     okay?

when the outside temperature is too cold, an endothermic animal can generate heat by shivering. endothermic animals must eat much more often than ectothermic animals since it takes energy to maintain a constant body temperature.

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