I believe the universe is 13.8 billion years old. Possibly longer, or possibly shorter. Correct me if I'm wrong.
Answer:
A zygote is the union of the sperm cell and the egg cell . Also known as a fertilized ovum, the zygote begins as a single cell but divides rapidly in the days following fertilization. After this two-week period of cell division, the zygote eventually becomes an embryo.
Explanation:
Answer: D. the mucus that helps the sperm travel to the uterus is too thick.
Artificial insemination is the technique in which the sperms are introduced into the female's cervix or uterine cavity. This results in pregnancy through in vivo fertilization. Women cervix is blocked by thick mucus which block the entry of sperms. Therefore, artificial insemination would be better in such situation than other forms of treatment.
Answer: ionotropic; metabotropic
Explanation:
A receptor can directly open the channel and exerts an ionotropic effect. The ionotropic effect takes place by the help of ionotropic receptors. These receptors are membrane bound receptor proteins which responds by the bonding of the ligand.
Due to ligand binding the channel opens and allows the movement of ions into the cells which helps in either increasing or decreasing the action potential.
The receptors can also bind to the ligand and produce metabotropic effect which means by the second messenger.
<span>Joints with no movement are called immoveable or fibrous joints.They are also called synathrosis, they are only separated by a thin layer of fibrous connective tissue e.g are the sutures of the skull.
Joints that are more loosely connected are called freely moveable or synovial joints. They are also called diarthrosis.The joints are held together by an articular capsule comprised of ligaments. A synovial membrane lines the inside of the capsule and secretes synovial fluid which lubricates the joint (hence it's name).</span>
