Answer:
(B) Boreal owls range over larger areas in regions where food of the sort eaten by small mammals is sparse than they do in regions where such food is abundant
Explanation:
Living beings exhibit various changes in the behavior and niche to make themselves better fitted to the conditions of their habitats.
Boreal owls feed on the other smaller mammals such as mice and shrews. These organisms that serve as their prey are relatively less abundant in the habitat. To ensure the food availability, the boreal owls occupy a larger area so that they can catch their less abundant food organisms.
In the habitats where the prey species of boreal owls are present in a larger number, these owls occupy smaller regions since the food organisms are easily available.
The answer to this question is the sacrum. The sacrum is a triangular bone that forms the base of the spinal column. This bone has a vital role in the skeletal system and also supports the weight of the upper body of a person and this bone and many nerves are inside the sacrum.
Answer:
Option A, keystone species
Explanation:
Keystone species are responsible for controlling any species from becoming dominant over all other species. The keystone species are found at the top of all the energy pyramids and food chains.
They control the explosion of population of prey and hence regulate the overall ecological diversity.
Some common example of keystone species is as follows –
Bison, prairie dog, large mammalian predators,
Hence, option A is correct
Answer:
The statement C that says ''is derived from the inner cell mass'' is false.
Explanation:
The trophoblast is a structure composed of a set of cells (cytotrophoblast and syncytiotrophoblast), which are shaping the outer layer surrounding a blastocyst, during the earliest stages of embryonic development that mammals pass.
The trophoblast provides nutritive molecules to the developing embryo and facilitates its implantation to the uterine wall due to its ability to erode the tissues of the uterus, that is, it is responsible for making it possible for the embryo to be implanted in the uterine endometrium. Thus, the blast can join the cavity formed by the uterine wall, where it will absorb nutrients from the fluid from the mother.
During the third week, embryonic development includes the development of the trophoblast. At the beginning, the primary villi are formed by the internal cytotrophoblast which is surrounded by the outer layer of syncytiotrophoblast. Then, the cells found in the embryonic mesoderm are directed to the primary villous in the third week of gestation and when it ends, the mesodermal cells begin to be singled out to form blood vessel cells.
