Explanation

1. Sodium (Na)
2. Hydrogen (H)
3. Carbon (C)
4. Oxygen (O)

Explanation

Ferrum is the Latin name for iron, which is why its chemical symbol is Fe.

It is a transition metal used widely in construction.

It is essential in the human body for forming hemoglobin.

Explanation

The number of different types of gametes is calculated using the formula 2ⁿ, where n is the number of heterozygous gene pairs.

In genotype AaBb, there are 2 heterozygous pairs (A/a and B/b), so 2² = 4 types of gametes: AB, Ab, aB, ab.

Explanation

Hyaline cartilage provides smooth surfaces for movement at joints and supports respiratory structures like the nose, trachea, and bronchi.

It is the most common type of cartilage and appears glassy under the microscope due to its fine collagen fibers.

Explanation

Tar is the major component of particulate matter inhaled in cigarette smoke.

It contains several carcinogens.

It is responsible for lung damage.

Explanation

Boron is a metalloid, showing properties between metals and non-metals.

Aluminum is a metal.

Phosphorus is a non-metal.

Explanation

The d subshell has 5 orbitals, each can hold 2 electrons, so total 10 electrons.

This is standard in electron configuration rules in chemistry.

Explanation

Molar mass of CO₂ = 12 (C) + 16×2 (O) = 44 g/mol

Number of moles = Mass / Molar mass = 60 / 44 ≈ 1.364 mol

Explanation

Fe = 56, N = 14 × 2 = 28, O = 16 × 6 = 96 → Total = 56 + 28 + 96 = 180 amu

This is the correct formula mass for Iron (II) Nitrate, Fe(NO₃)₂.

Explanation

The smallpox vaccine (1796) by Edward Jenner and rabies vaccine (1885) by Louis Pasteur were key biotech advances before the 20th century.

DNA structure was discovered later in the mid-20th century.

Artificial sweeteners also post-date that era.