Scientists believe that the earth's early atmosphere lacked gas because photosynthetic organisms did not yet exist

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.

A60-tooth gear is connected to a 72-tooth gear.if the smaller gear turns 12 times,how many turns does the larger gear make?

Match the reproductive structures based on their function and the system to which they belong. egg ovary sperm vas deferens vagina fallopian tube testis urethra