Answer: The electrons in an atom that take part in chemical bonding are the electrons in the outermost shell and they are called valence electrons.
Explanation: An atom is composed of three particles: protons, neutrons and electrons. The protons and neutrons occupy the centrally located nucleus while the electrons are located in the empty space outside the nucleus. Electrons are distributed around the nucleus in paths called electron shells. The electrons in the outermost electron shells are called the valence electrons. The valence electrons are the electrons that participate in chemical bonding. During chemical bonding, the valence electrons are either transferred from one atom to another or the valence electrons are shared between two atoms. A type of chemical bonding in which there is a complete transfer of valence electrons from an atom of a metal to an atom of a non-metal so that can attain octet or duplet structure of noble gases is called electrovalent or ionic bonding. A type of chemical bonding in which there is sharing of electrons between two atoms of non-metals so that both can attain the octet or duplet structure of noble gases is called covalent bonding.
(1) normally harmless cat antigens stimulated
<span>the immune system</span>
Answer:
Option-C
Explanation:
Habitat fragmentation is a process during which large habitat is fragmented in smaller habitats by man-made activities. Habitat fragmentation is a very harmful process as it is one of the major factors for the loss of biodiversity in the ecosystem.
Due to division of the larger habitat into the smaller fragments, the population present in the smaller area are more susceptible to extinction as they will not interbreed with the individuals of the population stuck in another small habitat.
Thus, Option-C is correct.
Answer:
d. on the plasma membrane
Explanation:
According to the endosymbiotic theory the origin of mitochondrion is from the prokaryotic organism: primitive host cell (future eukaryotic cell) engulfed prokaryotic cell (endosymbiont) that provided the functions that evolved into mitochondria. Both of them had benefits: the endosymbiont gained protection and some essential nutrients from the host, while host had the energy and oxygen source from the endosymbiont.
So, the plasma membrane of the endosymbiotic prokaryotic cell became the membrane of the mitochondrion.
