Answer:
Krypton
Explanation:
When Selenium forms an ion, it is trying to become krypton which is a noble gas.
Selenium belongs to the oxygen group on the periodic table. In this group, the atoms prefers to gain two electrons to complete their octet. When selenium gains two electrons, its octet is complete.
This will make the atom resemble krypton on the periodic table of elements.
This structure which is an octet confers a special stability on the element.
Surely, If cells did not work together in an organism, there won't be formation of new cells and life process would stop
<h3>Living organisms </h3>
Living organisms; be it plants or animals are any organic or living system composed of cells and function as an individual entity.
- All living organisms share a number of key characteristics or functions such as movement, respiration, homeostasis, reproduction, growth, evolution, competition and others.
- Animals and plants also posess systems such as the digestive, skeletal, transport, nervous, excretory, respiratory and reproductive system.
- Living organisms are also taxonomically classified as either unicellular microorganisms or multicellular plants and animals
So therefore, surely, If cells did not work together in an organism, there won't be formation of new cells and life process would stop
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Answer:
4) Each cytochrome has an iron‑containing heme group that accepts electrons and then donates the electrons to a more electronegative substance.
Explanation:
The cytochromes are <u>proteins that contain heme prosthetic groups</u>. Cytochromes <u>undergo oxidation and reduction through loss or gain of a single electron by the iron atom in the heme of the cytochrome</u>:

The reduced form of ubiquinone (QH₂), an extraordinarily mobile transporter, transfers electrons to cytochrome reductase, a complex that contains cytochromes <em>b</em> and <em>c₁</em>, and a Fe-S center. This second complex reduces cytochrome <em>c</em>, a water-soluble membrane peripheral protein. Cytochrome <em>c</em>, like ubiquinone (Q), is a mobile electron transporter, which is transferred to cytochrome oxidase. This third complex contains the cytochromes <em>a</em>, <em>a₃</em> and two copper ions. Heme iron and a copper ion of this oxidase transfer electrons to O₂, as the last acceptor, to form water.
Each transporter "downstream" is <u>more electronegative</u><u> than its neighbor </u>"upstream"; oxygen is located in the inferior part of the chain. Thus, the <u>electrons fall in an energetic gradient</u> in the electron chain transport to a more stable localization in the <u>electronegative oxygen atom</u>.
<u>Answer:</u> The mass of ice is 
<u>Explanation:</u>
We are given:
Area of Antarctica =
(Conversion factor:
)
Height of Antarctica with ice = 7500 ft.
Height of Antarctica without ice = 1500 ft.
Height of ice = 7500 - 1500 = 6000 ft =
(Conversion factor: 1 ft = 30.48 cm)
To calculate mass of ice, we use the equation:

We are given:
Density of ice = 
Volume of ice = Area × Height of ice = 
Putting values in above equation, we get:

Hence, the mass of ice is 
Answer:
we know, at STP ( standard temperature and pressure).
we know, volume of 1 mole of gas = 22.4L
weight of 1 Litre of hydrogen gas = 0.09g
so, weight of 22.4 litres of hydrogen gas = 22.4 × 0.09 = 2.016g ≈ 2g = molecular weight of hydrogen gas.
similarly,
weight of 2L of a gas = 2.88gm
so, weight of 22.4 L of the gas = 2.88 × 22.4/2 = 2.88 × 11.2 = 32.256g
hence, molecular weight of the gas = 32.256g
vapor density = molecular weight/2
= 32.256/2 = 16.128g
hence, vapor density of the gas is 16.128g.
Explanation: