Why do substances and circumstances sometimes harm the fetus and sometimes have no impact?

Where do we get our energy?

Which of the following involves only biotic factors? A. a pine tree absorbing light from the Sun B. a spider building a web in the corner of a building C. a duck catching and eating a snail D. an otter using a stone to break open a sea urchin

What might happen to the carbon cycle if dead organisms did not break down?

Are snakes vertebrates? :P

An atom with one valence electron joins an atom with seven. What is likely to happen to the atom with one valence electron? A. It will share its valence electron with the other atom. B. It will take one electron from the other atom. C.

What is the outermost connective tissue covering the spinal cord?

What three different types of atoms, or elements are present in monosaccharides

Which best describes the storage of the genetic code

If a female who is a carrier for colorblindness carries a man who is color blind. What is the percent chance their daughter will be colorblind.

Marissa is adding numbers in her head. Which part of her brain is she using?