What allows things to enter and leave a cell and is the gate keeper?

If a mutation in the dna of an organism results in the replacement of an amino acid containing a polar r-group with another amino acid containing a nonpoler group, how might the structure of the protien be affected

Tiny sacs in the lungs where oxygen exchange takes place. fundamental working unit of the nervous system. sometimes called the master gland.

What kingdom does paramecium and euglena belong to?

How is E. coli like a paramecium? A. Both produce essential vitamins. B. Both have a nucleoid. C. Both are single celled. D. Both have a contractile vacuole.

An adolescent girl who participated in unprotected intercourse requires an emergency contraception. which drugs could be prescribed? select all that apply.

Which of the following sense organs responds to chemical stimuli? a. eyes c. ears b. taste buds d. pain receptors

What is the interaction between mosquitoes an human beings called?

Which of the following is similar among all living organisms on Earth? cellular function social behavior physical appearance all of these

Lubricants reduce friction by replacing sliding friction with fluid friction, O A. True B. False O

Which of the following has the strongest gravitational pull on the earth? A. moon B. Earths magnetic core C. the atmosphere D. the sun