Answer to Question 1
A
Answer to Question 2
Nitrate can be toxic to humans, livestock, and pets by entering drinking water supplies. Consumption of unsafe levels of nitrate can result in illness and death. It is especially dangerous to pregnant women and small children. Nitrate ingested by humans goes through the stomach wall into the bloodstream. In the blood, it binds with hemoglobin, rendering it ineffective at carrying oxygen to the cells of the body. Hemoglobin turns from bright red to blue-brown. Lips of victims of nitrate poisoning often turn blue, and poisoned babies are called blue babies..
In addition to being directly toxic to humans and other animals, nitrate causes extreme environmental degradation. Because it is water soluble, nitrate can easily enter streams, rivers, and oceans. Hypoxia, or a deficiency of oxygen, in the Gulf of Mexico has been associated with the excessive amounts of nitrate entering in the Mississippi River draining into the Gulf. In the Gulf, it causes excessive growth of phytoplankton and algae that consume all the oxygen in the water. Consequently, the ocean is low or hypo in oxygen, so fish and shellfish cannot live, creating a dead zone in the Gulf.
The process of X inactivation
Photograph illustrating the development of a fetus
Milestones of Gross Motor Development in Toddlerhood
Development of Muscle
Embryonic development of shepherd’s purse (Capsella), a eudicot
Body plan of a lancelet