Explanation

Explanation

Acetyl Co-A is the first carbon compound that enters the Krebs cycle, combining with oxaloacetate to form citrate.

It is produced from pyruvate during the link reaction before entering the cycle.

Explanation

The common phrase is: "Hard work is the key to success," meaning it is the main factor in achieving success.

"Key" symbolizes access or unlocking success through effort.

Explanation

In most fungi, the nuclei are haploid (n) during the vegetative and asexual stages.

Diploid phase occurs briefly during sexual reproduction, followed by meiosis to restore haploidy.

Explanation

Friction always acts opposite to the direction of motion, resisting movement.

Since work = force × displacement × cos θ, and θ = 180°, cos 180° = –1, so work is negative.

Explanation

Deductive reasoning: General to specific.

Inductive reasoning: Specific to general.

Explanation

Alpha particles consist of 2 protons and 2 neutrons, making them identical to the nucleus of a helium atom (He²⁺).

They carry a +2 charge.

They are emitted during alpha decay in radioactive elements.

Explanation

The energy of a photon is calculated using the formula E = hf, where:

• h = Planck’s constant
• f = frequency of the photon

This shows that photon energy is directly proportional to its frequency.

Explanation

Excitation energy is the energy needed for an electron to jump from its ground state to a higher energy level.

It is less than ionization energy, as the electron remains bound to the atom after excitation.

Explanation