Members of phylum Porifera are commonly known as spongs. They are generally marine and mostly asymmetrical animals. These are primitive multicellular animals and have cellular level of organization (lacks tissues). These Organisms (belonging to phylum Porifera) lacks most of the structures that are present in multicellular organisms like digestive system, respiratory system, Brain etc
Body of Spongs are made up of spicules or spongin fibers and these organism contain a water canal system which helps them in digestion, reproduction and catching their food in marine habitat.
There are multiple reasons. 1) there are similar fossils found on different continents. 2) the continents shapes show that they could easily fit together. 3) there are similar rocks, minerals,and land forms on different continents. 4) there's evidence that there was once lush vegetation in areas with extreme cold.
1)How long did it take for the third of population to double?How long did it take for the population to double a third time? 2) 51 years
___________ A third time? It took 75 years for the population to double a second time and it took 51 years to double a third time. It will reach 8 billion at about 2024. 4.
Answer:
a) The mucosa is composed of thick, nonkeratinized stratified squamous epithelium.
d) The two layers of muscle in the superior one-third of the muscularis are skeletal
(B and E are repetition of A and D respecticely)
Answer:
1. asexual, mitosis 2. sexual 3. gametes, meiosis 4. haploid 5. sex cells
Explanation:
Asexual reproduction is the form of reproduction that occurs whereby there is no fusion of gametes or a change in the number of chromosomes. The produced daughter cells are genetically similar to the parent. the form of cell division that occurs here is through a process of mitosis.
Different organisms adopt different type of asexual reproduction including binary fission, spore formation, fragmentation etc.
Sexual reproduction in contrast generates genetically unique organism through the fusion of two different organisms sex cells. To accomplish sexual reproduction, gametes that are haploid through a process of meiosis must be produced which are the egg cell and the sperm cells (the sex cells). These haploid cells are produced only in the germ cells to ensure the production of a diploid zygote.