Those branch out further in a number of chorionic villi that make up the surface of the cotyledon. Due to the presence of a placental barrier the blood flow of the mother and fetus is not connected. Exchange of materials is performed with the help of diffusion, osmosis, or active transporti...
In animal mating systems, there are some clear steps that must be taken, including mate choice, sexual selection, and male competition. In this lesson, learn about animal mating by exploring what makes a great mate, selecting a mate, being selected, and male competition. Related to this Quest...
What is a non-avian theropod? What are non-placental mammals? What were the dominant species after every mass extinction? What are some invasive species in Ontario? What are exotic animals? What kind of ecosystem are exotic species especially threatening to?
There are a lot of animals in the world, with a lot of adaptations. Help students learn about them by trying out these fun animal adaptation activities. Explore our homework questions and answers library Search Browse Browse by subject
I've heard good things about placenta anti-aging cream, but I don't think I could ever get myself to use one with real animal placenta. It's kind of repulsive. I feel the same way about snail creams. But I wouldn't mind using placenta cream with plant placenta. But is it just as...
Placental mammals make up the majority of the mammal group. By having a placenta to carry nutrients to the embryo and filter away waste, the developing fetus can remain in the womb until it is more fully developed. While newborn placental mammals range from fully-formed but helpless, such as...
An umbilical cord, also known as a funis, is a tube found in placental mammals linking the unborn animal to its placenta. The placenta acts as a barrier within the uterus that stops many harmful substances from entering, as well as a store of energy and blood transfer for the developing ...
What animal category is a shark? Sharks belong to theClass Chondrichthyes. This includes all fish that have a skeleton made of cartilage. They're further divided into two Sub-classes. Elasmobranchii (sharks, skates and rays) and Holocephali (chimaera). ...
aThere are really only three ways to be a mammal, an animal characterized by hair, milk, a fused lower jaw and three bones in the middle ear. What distinguishes one mammal from another is how it bears its young. Giraffes, lemurs, narwhals and humans are all placental mammals, gestating ...
Which of the following is not a stage of cell cleavage? A. Morula B. Blastocoel C. Blastula D. Mesoderm E. Gastrula Which extraembryonic membrane has the function of storing the nitrogen wastes of the embryo? Is this function necessar...