What are stem cells and why are they important?

Unlike amphibians, reptiles- A. have lungs to oxygenate blood. B. have a closed circulation system in which blood circulates entirely within blood vessels. C.

What is the main function of the cell membrane of a cell? A. to exchange nutrients and the cells waste with the external environment B. to limit the size that cell can reach C. To organize the cell's internal contents D.

A mysterious disease has struck 15 horses at a farm with 100 horses. Doctors at the animal hospital test the blood of five of the sick horses and find that four of them show a type of bacteria never seen before. Answer the following: a.

How old is the pecten gibbus? and how long was it around for?

What do bottom dwelling fish, sponges and corals have in common

What part of the male urogenital tract is shared by the urinary and reproductive systems? the prostate gland the seminal vesicles the vas deferens the urethra

What is The relationship between the various levels of organization in plants and animals

What type of mountain ranges form at convergent plate boundaries

What is the actual temperature 3000km below the surface of the Earth?

In science the term theory is best described as: A) an untested guess B) an explanation based on scientific evidence C) a hunch D) speculation