Explanation

Nitrogen fixation refers to the process of converting atmospheric nitrogen (N2) into a usable form for plants.

This can happen through several methods: 

Atmospheric fixation:

• This occurs naturally when lightning strikes, breaking the strong nitrogen-nitrogen triple bond and creating nitrogen oxides that can dissolve in rainwater.

Industrial fixation:

• This involves using high-temperature and pressure processes, like the Haber-Bosch process, to convert nitrogen into ammonia.
• This method is crucial for industrial agriculture. 

Biological fixation:

• This process is carried out by certain bacteria, such as those found in the root nodules of legumes (like peas and beans), or free-living bacteria in the soil.
• These bacteria can break down the nitrogen molecule and convert it into ammonia or other usable nitrogen compounds. 

Explanation

If the force acting on a body is plotted along the y-axis and the displacement covered as a result is plotted along the x-axis, then the work done is given by the Area under the curve.

Explanation

Protozoa are single-celled eukaryotic organisms (meaning they have a nucleus) and heterotrophic (meaning they cannot produce their food and must consume it).

These characteristics are also shared by animals. 

Explanation

The relative atomic mass of a neutron is approximately 1.0087 amu (atomic mass units), slightly more than that of a proton (about 1.0073 amu)

Explanation

In mitochondrial DNA, the codon AGG typically codes for a stop codon. 

Standard genetic code:

• In the standard genetic code, AGG codes for the amino acid arginine. 

Mitochondrial code deviation:

• However, mitochondrial DNA often uses a slightly different genetic code.
• In many mitochondrial genomes, including those of vertebrates, the codons AGA and AGG are reassigned as stop codons, meaning they signal the end of protein translation. 

Explanation

To determine the limiting reagent, use the balanced chemical equation:

C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O

From the equation:

- 1 mole of ethanol reacts with 3 moles of O₂.

You have:

- 2 moles of ethanol

- 6 moles of oxygen

Required O₂ for 2 moles ethanol = 2 × 3 = 6 moles

Since you have exactly 6 moles of O₂, both ethanol and oxygen are completely consumed.

Explanation

 The lifetime of an electron in a metastable state is significantly longer than in an ordinary excited state, typically by 10³ to 10⁵ times. 

Ordinary excited states have lifetimes on the order of 10⁻⁸ seconds. 

Metastable states have lifetimes that can range from microseconds to milliseconds and even longer, being orders of magnitude longer than typical excited states.

Therefore, options like 10³ or 10⁵ are appropriate estimations for how much longer a metastable state lifetime is compared to an ordinary excited state. 

Explanation

The fertile time in the menstrual cycle is typically considered to be 9–15 days,

Especially for individuals with a 28-day cycle, with the most fertile days being around ovulation

Which occurs around day 14 of a 28-day cycle.

However, the fertile window can vary depending on the length of the menstrual cycle and individual factors.

Encompassing the days leading up to ovulation and the day of ovulation 

Itself, as sperm can live for several days in the female reproductive tract, while the egg lives for about 24 hours. 

Explanation

Simple squamous epithelium lines the alveoli, allowing for efficient gas exchange due to its thin, flat cells. 

Explanation

 When capacitors are connected in parallel, their capacitances add up directly:

C_eq = C₁ + C₂ + C₃ = 2 + 2 + 2 = 6 µF