The embryos of complex multicellular animals must establish spatial coordinates in order for development to proceed. an important reference coordinate for developing frogs is the (a) location of the vegetal pole. (b) location of the animal pole. (c) point of sperm penetration. (d) location where gastrulation begins. (e) direction of the sun.

__1__ is a climate cycle where the temperature of the __2__ ocean changes because of movements of air and ocean currents. during this period, the trade winds in the south __3__ , causing the __4__ water to move from the __5__ region to the __6__ region. 1) el nino or the monsoon 2) atlantic, indian, or pacific 3) reverse, strengthen, or weaken 4) cold or warm 5) eastern or western 6) eastern or western

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.

Ialready know the answers to these questions and they are on the attachment. but i just need to know why that answer is the correct one. plz asap! this is for a report that i need to email by 10!