With the upcoming presidential election, Ira decided to create a survey to find out who might win. He carefully created a valid survey and gave it to five of his closest friends. He then tallied the results from the surveys and published his data in the school newspaper. Which of these would be a reason why Ira's results are not valid?
A) The survey was not good enough.
B) The sample size of five was too small.
C) There is not problem; the results are valid.
D) He only published his data in a school newspaper.

I’m doing some practice exam questions for biology, and i’m not sure how to do these 3 parts to the question.

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.

The mammal pictured below is a silvery mole rat. which statement is an inference based on the picture? the animal is ugly. the animal has hairless feet with sharp claws. the animal has prominent upper and lower incisor teeth. the animal likely has poor vision since its eyes are so small.