A barrier that allows some substances in while keeping other

substances out is said to be

a. subpermeable

b. selectively permeable

c. superpermeable

d. impermeable

Why is the ventricle of a frogs heart thicker and more muscular than the atria in the heart?

In the alternation of generations life cycle the spore undergoes mitosis to become a a. gametophyte. b. sporophyte. c. spore. d. gamete.

Liver and muscle biopsies reveal that glycogen content in the liver is normal but muscle glycogen is elevated. the biochemical structure of glycogen in both tissues appears to be normal. what is the problem

List the 4 "problems" of living on land that plants had to overcom

Is light an external or internal stimulus for plant and how does plant react to light

How many atoms lined up side by side would equal the thickness of a book page?

If an ambulance hits someone on the road while transporting someone to a hospital, do they bring that person with them too?

Cell biologists have introduced radioactively labeled carbohydrates, fats, and amino acids to living cells, allowed time for cell metabolism, and then placed the cells in a blender and separated out the various cell organelles from the cytoplasm.

Increased production of goods makes our lives more comfortable, but causes an increase in the demand for energy and other resources. One negative impact of this situation on ecosystems is an increase in

One of the most common causes of pneumonia is Streptococcus pneumoniae, a gram-positive bacterium. Surrounding the bacterium is a thick structural component layer known as a capsule.