The hormone secreted by the blastocyst that is found in the mother's urine and is the basis for most pregnancy tests.

Imagine that you are studying a new species. As you examine the circulatory system, you note that the diameter of the vessels grows smaller and smaller as you move farther from the heart, but the blood is always contained within vessels. If you want to place this new species into a group whose membership is solely based on whether the animals included share this described type of circulatory system, which animals would be included in this group? Check all that apply.

_____ all mollusks _____ frogs _____ fish _____ housefly

Why are massive main-sequence stars not likely to have planets that contain life?

a. The life zones around these stars is too small. b. These stars would sweep away all of the material from which planets could form. c. These stars are too hot to allow water to exist as a liquid on any planets that might form. d. These stars are on the main sequence for too short a time to allow life to evolve. e. These stars are almost always binaries and planetary orbits are unstable around binaries.

Which of the following was proposed by Mendel after working with garden pea plants?

a. The physical observation of a recessive trait means that the organism lacks any dominant versions of that characteristic. b. An organism’s dominant traits disappear in the offspring of a hybridization. c. The physical observation of a dominant trait means that the organism has two recessive versions of that characteristic. d. An organism’s dominant and recessive traits blend to form a codominant allele.

Eukaryotes that are not closely related and that do not share many anatomical similarities can still be placed together on the same phylogenetic tree by comparing their _____

A) plasmids B) mitochondrial genomes C) homologous genes that are poorly conserved D) homologous genes that are highly conserved