What is a group of cells that secrete substances into the blood or directly into an organ

When estuarine water forms layers of different density that do not mix, what is it is called?

How does a habitat, population, community, and ecosystem differ?

Electromagnets are the result of A. two positively charged ends. B. an electrical charge. C. generators. D. the Earth's magnetic poles.

Are red tail hawks sexual or asexual

Which of the following is one effect storm waves have on a beach?

Give two examples of equations for the synthesis of transuranium elements by transmutation

In muscle the source of a "phosphate molecule needed to recharge an adp molecule to an atp molecule" is

5. What would occur if ... a ... the wildflower population decreased?

Most crimes involve some evidence relating to the human body; for that reason, what related science is frequently used in forensic investigations? a) psychiatry b) physics c) botany d) biology

When evaluating your resources for authority, which of these question would you ask? A. Is the material too general, too technical, or just right for my needs? B. How recent is the information? C. Has this author been cited in other resources?