Pesticides often do not just kill the target pest but also poison inects in and
around the fields. These insects with the pesticides can be eaten by other animals and poison them.
Some pesticides are suspected of disrupting the
of wildlife and people. These
chemicals
because they are fat soluble and get passed up the food chain
by
Unlike pesticides, fertilizers are not directly toxic but their presence in
freshwater and marine areas alters the
system, and in consequence the species
composition of specific ecosystems. Their most dramatic effect is
resulting in an
explosive growth of algae due to
nutrients. This depletes the water of dissolved
oxygen, which in turn can kill fish and other aquatic life.

This organism is not capable of performing photosynthesis. (horseshoe crab) true false

Bisphenol a (often called bpa) is a chemical found in products that people use every day, from water bottles to food containers to children's toys. unfortunately, bpa leaches out of its many products and makes its way into our bodies. what are the health effects of bpa exposure? ongoing research is finding that elevated exposure to bpa can affect a wide variety of developmental and physiological processes, but one of the first studies of bpa's health effects came about because of a simple mistake in the lab. at a laboratory at case western reserve university in 1998, geneticist patricia hunt was making a routine check of her female lab mice. as she extracted and examined developing eggs from the ovaries, she began to wonder what had gone wrong. she noticed that many of the eggs showed problems with their chromosomes, and some had irregular amounts of genetic material, which can lead to miscarriages and birth defects in mammals. she learned that a lab assistant had mistakenly washed the plastic mouse cages and water bottles with a harsh soap, releasing bpa from the plastic. knowing that bpa is an endocrine disruptor, a chemical that can enter organisms and mimic hormones, hunt set out to discover whether it had adversely affected her mice.

'which of these statements about the scientific method is not true? all experiments must follow the same number of steps in the procedure. experiments may be repeated several times. some unexpected results can be beneficial. experimental results may or may not support the hypothesis.