What system also sends signals, but they are chemical signals (hormones)

Weights of golden retriever dogs are normally distributed. samples of weights of golden retriever dogs, each of size nequals15, are randomly collected and the sample means are found. is it correct to conclude that the sample means cannot be treated as being from a normal distribution because the sample size is too small? explain.

Describe speciation of the galapagos island finches in terms of geographic isolation

Iron reacts with oxygen to produce iron oxide (rust). this reaction is represented in an equation as 4fe + xo2 → 2fe2o3. identify the value of x that will balance the equation.