Explanation

Jaws were absent in the class Ostracodermi.

Ostracoderms are an extinct group of jawless fish that lived in the Paleozoic era.

They are characterized by their armored bodies and lack of jaws, unlike later vertebrates that evolved jaws.

Explanation

Chondrichthyes (cartilaginous fish, such as sharks and rays) and Osteichthyes (bony fish) differ in several characteristics.

One key difference is the presence of spiracles.

Spiracles are small openings behind the eyes of some cartilaginous fish that allow water to pass over the gills when the mouth is closed.

Bony fish generally do not have spiracles.

Explanation

Water is the only known non-metallic substance that expands when it freezes

its density decreases and it expands by approximately 9% by volume.

Explanation

Tetrafluoroethane (HFC-134a) is commonly used in modern refrigerators.

Unlike Freon, it does not deplete the ozone layer.

Explanation

In chromatographic analysis, the principle used is adsorption, where the components of a mixture interact with the stationary phase and are separated based on their differing affinities for the stationary phase.

Explanation

 Steroid hormones are hydrophobic molecules synthesized from cholesterol that are able to diffuse through the plasma membrane Examples of this group are sex hormones, such as testosterone, estrogen, progesterone, as well as thyroid hormones, such as glucocorticoids and vitamin D.

Explanation

Explanation

The longest cell in animals is the nerve cell.

Nerve cells are also known as neurons and in the human body, they can be up to 3 feet long.

Explanation

Luteinizing Hormone (LH) is a glycoprotein hormone.

It is composed of two subunits, alpha and beta, with attached carbohydrate groups.

LH plays a crucial role in regulating the reproductive system, particularly in triggering ovulation in females and stimulating testosterone production in males.

It is not a steroid, peptide, or lipid, but specifically a glycoprotein.

Explanation

One Coulomb (C) is the unit of electric charge and is defined as the amount of charge transported by a steady current of 1 Ampere (A) flowing for 1 second.

Mathematically: 

1Coulomb=1Ampere×1second

This means that if a current of 1 Ampere flows through a conductor for 1 second, the total charge transported is 1 Coulomb.