Which of the following reactions are exothermic?

 

$$\begin{gathered} 1) C + O2 → CO2 \\ 2) 2Mg + O2 → 2MgO \\ 3) CuSO4 + 5H2O → CuSO4.5H2O \\ 4) All the above \end{gathered}$$

Estrogen is a group of steroid hormone that control the development and maintenance of an individuals feminine characteristics. Natural estrogen exists in men as well as women and are found in higher amounts in women Especially in those of reproductive age.

Estrogens are hormones which are responsible to the body functions of the female body system such as menstruation, development of the female body such as pubic hair, breasts and development of the proportions of the body.

Lipids act as best energy storage molecules as the cleavage of fatty acids produces both energy and metabolic water which is a main component in almost all lipids.

Electrons orbit around the nucleus is correct about them.

The simplest form of matter that has a unique set of properties and is cannot be broken down into simpler substances by chemical means is called an Element.

An Atom is the simplest form of an element.

The simplest form of some elements is a Molecule. When an element consists of two identical atoms it is called a diatomic molecule.

A substance that contains two or more elements chemically combined in a fixed proportion is called a Compound.

Most of the ozone in the atmosphere is found in the layer of stratosphere, which begins about 10.16 kilometers (6.10 miles) above Earth's surface and extends up to about 50 kilometers (31 miles) altitude.

The Secondary Structure of a Protein is option B)

The Secondary Structure of a Protein results from Hydrogen Bonds.

Fructose is an Organic molecule among the given options.

Organic Molecules :

An organic molecule is one which contains carbon, although not all compounds that contain carbon are organic molecules. Noticeable exceptions are carbon monoxide (CO), carbon dioxide (CO2), carbonates (e.g. calcium carbonate), carbides (e.g. calcium carbide) and cyanides (e.g. sodium cyanide). Pure carbon compounds such as diamond and graphite are also not organic compounds. Organic molecules can range in size from simple molecules to complex structures containing thousands of atoms.

Although carbon is present in all organic compounds, other elements such as hydrogen (H), oxygen(O), nitrogen (N), sulfur (S) and phosphorus (P) are also common in these molecules.

In simple, Molecules needed for life that have carbon are called Organic Molecules.

Osmosis is the process in which water molecules move from a region of higher water potential to a region of lower potential down a water potential gradient across a partially permeable membrane. It doen't requires any additional energy to do this work. 

So, Osmosis is a Passive.

Active and passive transport processes are two ways molecules and other materials move in and out of cells and cross intracellular membranes.

1. Active transport is the movement of molecules or ions against a concentration gradient (from an area of lower to higher concentration), which does not ordinarily occur, so enzymes and energy are required.

2. Passive transport is the movement of molecules or ions from an area of higher to lower concentration. Passive transport occurs because of the entropy of the system, so additional energy isn't required for it to occur.

3. Active transport requires energy to proceed, while passive transport does not require the input of extra energy to occur.

All chemistry is based on sharing electrons. A chemical bond forms when two atoms transfer or share outer electrons to complete their outer shells.