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.

c) 50% there are four chromosomes. after crossing over, 2 of the four have been changed. that means any gamete has a 2 in 4 chance or 50% chance of receiving the mutated chromosome.

sorry to break it to ya but no one can answer your question it's just

jk but i am serious about the part that most people cant answer it beacuse you did not mention the section you are talking about. but it would if you added some detail and were a bit more specific.

it is called the mitotic spindle

the rocks are classified by the geological process they are formed by. the three main groups of rocks are igneous, metamorphic, and sedimentary. minerals are not they are classified under the chemical classes they are in. these groups include silicates, sulfates and carbonates.