18. Circle the letters of the sentences that are true about aquifers. a. They are permeable rock layers that are saturated with water.
b. They are recharged or refilled as rainwater seeps into them.
c. They are often made of shale and unbroken granite.
d. Many people rely on aquifers for drinking water.

Describe two recent or ongoing space missions.

Food webs - transferring energy and matter from one level to another. here you see four food webs. one or more are incorrect. which food web(s) show the correct sequence of organisms, from start to top level consumer? a) a b) d c) c d) a and d

Gregor mendel is best known for his work with pea plants and for uncover many of the mysteries of genetics. one of his major findings stated that there were specific, physical units of inheritance that are transmitted during reproduction. what is the the name given to these units of inheritance which can be found on chromosomes? a) centromeres b) cytoplasm c) genes d) nucleotides