The correct answer is D. Bears dig big holes in the ground to protect their young
Explanation:
The Earth spheres include the biosphere (life in the Earth), the hydrosphere (water bodies), the geosphere (rocks and other elements that compose land and soil), and the atmosphere (gases that compose the air). In this context, there is an interaction between two spheres: the biosphere and the geosphere, when a bear digs holes in the ground because a living organism that is part of the biosphere is modifying the structure and shape of superficial soil, which is part of the geosphere.
The third answer is the one you want. You have to have an adjustable density. All other things being equal, if the tanks you use for holding just water when filled with water will let the sub sink, because the sub is made of a dense metal like iron or steel.
If on the other hand you fill these tanks with air, the net density will be below one and the sub will rise.
Answer:
Explanation:
Atom X,
Neutron num = 4, Mass num = 7
Therefore, proton number = Mass num - Neutron num
= 7 - 4
= 3
Atom Y,
Neutron num = 5, Mass num = 9
Therefore, proton number = Mass num - Neutron num
= 9 - 5
= 4
1) False. Atom X belongs to group 3 while atom Y belongs to group 4
2) False. Atom X is in a column on the left of Atom Y
3) True. Atom X and atom Y belong to the same period two on the periodic table
4) Fasle. Atom X and Y are not isotopes because they do not have the same atomic number.
Isotopy is a phenomenon whereby atom of same element have same atomic number but different mass number
The answer should be "by convection" not by radiation.