Some living thing's bodies are weaker than others. For the species to live, the strong ones of the species will not get sick, reproduce and create strong offspring. The weak will die out.
In the small intestine, cells contain microvilli, which are tiny hair-like projections that increase nutrient absorption. These projections increase the surface area of the small intestine allowing more area for nutrients to be absorbed.
Answer:
The reason that there is no fruit even the plant produced healthy flowers maybe because
1. absences of pollinators due to declining poliinator population
2.weather conditions are preventing pollination
3. prevalence of flooding
Explanation:
1.Fruits are direct result of pollination. Due to the decrease in the number of pollinators especially orchid bees, some fruit bearing plants produce flowers but no fruit.
Bees decline their population because of parasites, diseases, exposure to chemicals and other environmental factors.
2.Unfavorable factors may prevent the agents of pollination to do their jobs. Bees and other insects may be hindered by wet or cold weather or some use of chemicals.
3.Brazil nut grow in lowland rainforest where there is no flooding.
Answer: D
Explanation:
During embryogenesis, hematopoiesis begins in week 3 in the Yolk Sac, in Pander´s Island or Wolff´s Island, commonly known as the "blood islands". These blood islands develop from the umbilical vesicle, allantois, and chorion. In week 5, blood production starts on the fetal liver, and finally, at week 12 it begins in the bone marrow, spleen and, thymus.
Explanation:
Complete answer:
A mature erythrocyte lacks nucleus and mitochondria so as to make a place for the accommodation of more hemoglobin and hence more oxygen molecules. Lack of such organelles also provides the peculiar biconcave appearance of RBCs that aids in efficient diffusion. Young mammalian RBCs are nucleated.
