Answer: D). Primary species have large numbers of offsprings, and climax communities contain species that have small numbers of offsprings.
An ecological succession is a process of gradual changes occurs in a biological community with respect to changes in the non-living abiotic factors (water, air and sunlight) and with respect to time until the ecosystem attains stability. Primary or pioneer species are the species which invade the previously barren and primitive landmass for their survival. These species make the environment suitable for the growth of other species. These grow and develop in the initial stages of succession. These species are simple organisms which reproduce asexually and produces large number of offsprings. Examples are lichen and moss. Lichen grows on the surface of rocks and acids released by them causes withering of rocks into soil which facilitate the growth of mosses and other plants. Climax community develops in an ecosystem after replacing many previously inhabiting species. Climax community develops in the end of the ecological succession. It contains species which are highly complex and uses sexual reproduction for the production of offsprings which are less in number as compared to those produced by pioneer species by asexual reproduction.
Some don't have any able to see effects,but some cause diseases
Answer:
Following Statements are true.
1. Cells receive molecular signals that communicate their position in relation to other cells.
3. Differential gene expression affects the developmental process in animals.
4. Positional information controls pattern formation.
6. Homeotic genes code for transcription factors that control the development of segment-specific body parts.
Explanation:
The formation of an eukaryotic organisms's spatial organization which includes organ formation and tissue arrangement is called as Pattern formation.
Molecular signals are received by cell. This phenomenon collectively refereed as positional information. Through this phenomenon cells are informed about their locomotion with respect to body axes and other cells. Regulation of pattern formation is controlled by Positional information.
When body axes is established a gene called homeotic gene start working as regulatory genes. This gene identify specific body segment in an organism which results in the formation of segment-specific body structures in the correct locations on the body.
Bacteria and Fungi are the two primary decomposers
Explanation:
<u>Bacteria: </u>Bacteria are known as microscopic single celled organism. Their existence is between inside as well as outside the organism. The use of bacteria is in medical and industrial processes. They are first organisms in earth. Bacteria can survive in worst condition. There are huge number of bacteria. So, it is classified according to their structure and shape.
The life cycle of bacteria can be divided into log phase, lag phase, the stationary phase and Death phase. In lag phase bacteria don’t grow they produce amino acid and protein and make copies of DNA. They make themselves ready for division. In log phase bacteria rapidly multiply itself through binary fusion. In the stationary phase the growth of bacteria is dwindles because of lack of space and accumulating waste. The last phase is death phase where bacteria loss its ability of reproduction.
<u>Fungi:</u> Fungi is same like bacteria play vital role in ecosystem. They are also decomposer. The first way of fungi life cycle is based on spore phase. They begin with haploid. They have one copy of all their genetic material. The second stage is mycelium stage where fungi reproduce asexually.
