Explanation

Chondrichthyes, which include sharks, rays, and skates, have a high concentration of urea in their blood.

This is due to their method of osmoregulation, which helps them maintain fluid balance in their often saline marine environments.

Explanation

The reason is that the rails expand in summer

. The gap is provided to allow for this expansion.

If no gap is left the expansion in summer will cause the rails to bend sideways

This may result in train accidents.

Explanation

Tyloses are outgrowths from xylem parenchyma cells

They grow into the lumen of tracheary cells through pits, balloon out, and occlude the cell interior.

Tyloses are typically associated with the process of defense against pathogens

They are commonly found in the xylem of certain trees and plants.

Explanation

Oceans cover about 70 percent of the Earth's surface and about 97 percent of all water on and in the Earth is saline—there's a lot of salty water on our planet.

Explanation

Explanation

 None of these options are completely incompressible.

While solids are the least compressible among the three states of matter (solid, liquid, and gas), all of them can be compressed to some degree. 

Explanation

 Morphology:

This field studies the structure of words, including their parts of speech, prefixes, suffixes, and how they are formed.

Syntax:

This field examines how words are put together to form sentences

Etymology:

This field investigates the origin and historical development of words

Explanation

To induce fission in Uranium-238 (²³⁸U), you need Fast neutrons. 

Fast Neutrons:

Fast neutrons have sufficient kinetic energy to overcome the repulsive forces within the nucleus and initiate fission

Explanation

 The science of treating the muscular and skeletal system, also known as the musculoskeletal system, is called orthopedics. 

Explanation

Echidnas and platypus are the only egg-laying mammals, known as monotremes.