Explanation

Scorpions and spiders both belong to the class Arachnida.

This class includes arachnids, which are characterized by having eight legs and lacking antennae.

Explanation

The periosteum is a fibrous connective tissue membrane that covers the outer surface of most bones, providing blood supply and contributing to bone growth and repair. 

Explanation

The pair of physical quantities with the same dimensions is Work and Energy.           

Both work and energy have the same dimensional formula: ML²T⁻²

Explanation

The exoskeleton of coelenterates is made of Calcium carbonate. 

Coelenterates like corals primarily have exoskeletons composed of calcium carbonate

Explanation

Sieve tubes and companion cells are absent in the phloem of pteridophytes.

Explanation

Gap junctions are specialized structures that allow direct communication between adjacent cells.

They are formed by connexin proteins that create channels enabling the exchange of ions, metabolites, and other small molecules between cells. 

Explanation

In humans, the type of implantation is endometrial implantation,

which occurs when the embryo embeds itself into the lining of the uterus (endometrium).

Explanation

Animals that eat plants exclusively are herbivores

Animals that eat only meat are carnivores.

Animals that eat both plants and meat are called omnivores.

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ND18-1-2023

Explanation

Convex lenses are used to treat presbyopia, hypermetropia, and aphakia

hypermetropia, and hyperopia, is a condition of the eye where distant objects are seen clearly but near objects appear blurred.

Explanation

Eugenics is the science of improving the human species by breeding out disease and disabilities, aiming to enhance the genetic quality of the human population.

This concept has been widely criticized and discredited due to its association with unethical practices, such as forced sterilization and discrimination.