Elise is beginning to learn how to write. He can hold a pencil in one hand and steady the paper with his other hand. This new ability to coordinate the duties of his right and left hands is likely due to ___.

the growth of her corpus callosum

Explanation:

The corpus callosum is known to be the connector between brain hemispheres, which means that it connects the left side of the brain to the right side. It is this connection that permits for the transfer of information between the two sides of the body. Hence the ability for Elise to write with one hand and steady the paper with the other is as a result of a connection between her left and right brain, which shows growth in her corpus callosum.

to stay where they were until m sent for

explanation:

allergens: overstimulate the nerve system

neurotics: attack nerve cells

mutagens: damage or otherwise alter dna sequence

generators: cause defects during growth and development  

carcinogens: cause unchecked cell growth

i hope you get the idea according to me these are the effects that happened.