Explanation

 In Einstein's universe, the fourth dimension is time. 

Einstein's theory of relativity revolutionized our understanding of space and time, merging them into a single four-dimensional continuum called "spacetime".

Time is considered the fourth dimension within this framework. 

Explanation

In the dark reaction (also known as the Calvin cycle), the first stable compound formed is 3-phosphoglyceric acid (3-PGA), which is a three-carbon compound.

Hence, the correct answer is c) 3. 

Explanation

 Ostia are small pores on the sponge's body that allow water to flow in, leading to the central cavity called the spongocoel. 

Explanation

A metastable state is an excited state of an atom or molecule that has a significantly longer lifetime compared to other excited states, but is still shorter than the ground state.

This means that an electron in a metastable state can stay in that state for a relatively long time before transitioning back to a lower energy level. 

Explanation

Explanation

Endometriosis is a condition where tissue similar to the lining of the uterus grows outside the uterus.

This tissue can cause pain and infertility, primarily in women.

There is very strong evidence linking endometriosis to female infertility.

Studies show that a significant portion of women with infertility also have endometriosis.

While endometriosis can rarely occur in men, it is not considered a significant cause of infertility in males. 

Explanation

Most coenzymes are actually vitamins or derived from vitamins, meaning they are essential organic compounds needed in small amounts for normal metabolism

Explanation

 The proper term for "X" is Plane of symmetry.

A plane of symmetry is an imaginary plane that divides a crystal into two halves, where each half is the mirror image of the other. 

Explanation

 When a sound wave moves from one medium to another, the quantity that remains the same is its frequency. 

The frequency of a sound wave is determined by the source of the sound and doesn't change when it enters a different medium.

However, the wavelength and speed of the wave can change depending on the properties of the new medium. 

Explanation

A liquid crystal is a state of matter that exhibits properties of both liquids and crystals.

It requires the molecules to have a specific structure, often long and rigid, to form ordered phases.

While soap can form structures similar to liquid crystals when mixed with water (forming micelles), pure soap is not a liquid crystal.

The other options listed, DNA, cholesteryl format, and engine oil, can all exhibit liquid crystal properties under certain conditions.