Mutualism is a way of life in which two species that could live independently come together permanently or sporadically and each one puts something on their side for the survival of both. In nature there are many types of mutualism, for example, the spider and the toad, the narrow-billed toad is an ally of a type of tarantula that usually devours small frogs, but what, in exchange for this small amphibian to eat the parasites that affect its eggs, the arachnid allows it to live in his burrow underground and in return defends him from possible predators, like owls, throwing to them urticating hairs in their eyes.
In the periodic table, the atomic radius of the atoms decrease from left to right. This means that Carbon is smaller than Boron. So from the choices you can rule out the first and third choice.
Now, the reason why Carbon is smaller than Boron is because Boron has more protons and as the protons increase it attracts the electrons closer, which makes the atom smaller.
Carbon has more protons, so it exerts a greater pull. The answer is then Option 2: Boron has a larger radius and the protons in carbon exert a greater pull.
As for the second question, a compound is defined as a substance that is made up of two DIFFERENT elements that are chemically bonded. If you look at the second option, it is a compound. It is made up of hydrogen and oxygen atoms.
The answer is then option 2.
A chemical reaction bonding monomers together to make a polymer
I believe that secretion into the tubular fluid occurs when the principle cells in the Proximal convoluted tubule secrete H+ into the urine.
Tubular secretion is the transfer of materials from peritubular capillaries to the renal tubular lumen; it is the opposite process of reabsorption. This secretion is caused mainly by active transport and passive diffusion.
Answer is A all living things need to go through the photosynthesis cycle and need oxygen to sustain life