Explanation

In a reversible adiabatic process, there is no heat exchange with the surroundings, meaning the system is isolated in terms of heat.

Since entropy is a measure of:

• heat energy dispersal
• no heat is exchanged
• the entropy change in a reversible adiabatic process is zero.
  

Explanation

In the taxonomic hierarchy, the rank that comes directly below the class is the order.

The full hierarchy from broader to more specific categories is:

1. Domain
2. Kingdom
3. Phylum
4. Class
5. Order
6. Family
7. Genus
8. Species.

Explanation

In gastropods (such as snails and slugs), the veliger stage is a crucial developmental phase following the trochophore stage.

During the veliger stage, the larva develops a shell and ciliated structures that help it swim.

Explanation

The nacre is continuously deposited onto the inner surface of the shell

The iridescent nacreous layer is commonly known as the mother of pearl

Nacre is secreted by the epithelial cells of the mantle tissue of various molluscs.

The layers of nacre smooth the shell surface and help defend the soft tissues against parasites 

Explanation

 In a p-n-p transistor, the collector current is slightly less than the emitter current.

This is because a small portion of the current flowing from the emitter to the base recombines with electrons in the base region, reducing the current that reaches the collector. 

Explanation

In a zero-order reaction, the rate of reaction is independent of the concentration of the reactants and is equal to the rate constant k.

The rate equation for a zero-order reaction is  Rate=k, where the rate of reaction is constant and does not change with varying concentrations of reactants. 

Explanation

PHRV (Polyhydroxyalkanoates) is a type of biodegradable polymer.

It is produced by microorganisms and can be broken down by natural processes, making it environmentally friendly compared to other polymers.

Explanation

In an isothermal process, the temperature of the system remains constant.

According to the first law of thermodynamics, for an ideal gas, if the temperature is constant, the internal energy does not change.

Therefore, the change in internal energy is zero (ΔU = 0).

Explanation

It is estimated that about 99.9% of all species that have ever existed on Earth are now extinct.

This figure underscores the vast extent of extinction events throughout:

• Earth's history
• reflects the dynamic 
• often unstable nature of life on the planet.

The remaining 0.1% of species are the ones that are still extant today.

Explanation

The fluid mosaic model describes the structure of the plasma membrane of both prokaryotic and eukaryotic cells.

This model illustrates the membrane as a dynamic and flexible structure with various proteins floating in or on the fluid lipid bilayer.