9.
which is true of hydroxide ions?
they are not found in pure water.
they have a negative charge.
they dissociate to form protons.
they contain two hydrogen atoms.

They have a negative charge.

Explanation:

Acids may be defined as the substance that has hydrogen ions whereas the base has the ability to produce hydroxide ions. Both the hydrogen and hydroxyl ions carry charge over them.

Hydroxide ions carry negative charge over them. Hydroxide ions are present in bases as well as in the water molecule. Hydroxide ions can not be dissociated to form the protons. A single hydrogen atom is present in hydroxide ions.

Thus, the correct answer is option (2).

hormones in blood stream

image: dtc.ucsf.edu

endocrine glands secrete hormones into the blood stream near them; the hormones then travel in our bloodstream until it reaches its destination, called a target cell, in distance parts of the body. in the target tissue, hormones lock onto the target’s plasma membrane, called the receptor site.

answer: - b cells

explanation: -

so, the b cells mediate their action by identifying the antigens present on the surface of the pathogens and then producing antibodies in return to mediate its effect.