After your first exposure to a pathogen, you have memory T cells that will remember the antigen of the pathogen son in the future if you would come in contact with the same pathogen your body will recognize it right away and be able to kill it much faster
Answer:
you would find it in section 3 as these are semi-metals
Explanation:
In order to determine if the ion is positively charged or negatively charged
This hypothetical process would produce actinium-230.
<h3>Explanation</h3>
An alpha decay reduces the atomic number of a nucleus by two and its mass number by four.
There are two types of beta decay: beta minus β⁻ and beta plus β⁺.
The mass number of a nucleus <em>stays the same</em> in either process. In β⁻ decay, the atomic number <em>increases </em>by one. An electron e⁻ is produced. In β⁺ decay, the atomic number <em>decreases </em>by one. A positron e⁺ is produced. Positrons are antiparticles of electrons.
β⁻ are more common than β⁺ in decays involving uranium. Assuming that the "beta decay" here refers to β⁻ decay.
Gamma decays do not influence the atomic or mass number of a nucleus.
Uranium has an atomic number of 92. 238 is the mass number of this particular isotope. The hypothetical product would have an atomic number of 92 - 2 ⨯ 2 + 1 = 89. Actinium has atomic number 89. As a result, the product is an isotope of actinium. The mass number of this hypothetical isotope would be 238 - 2 ⨯ 4 = 230. Therefore, actinium-230 is produced.
The overall nuclear reaction would involve five different particles. On the reactant side, there is
On the product side, there are
- one actinium-230 atom,
- two alpha particles (a.k.a. helium-4 nuclei),
- one electron, and
- one gamma particle (a.k.a. photon).

Consider: what would be the products if the nucleus undergoes a β⁺ decay instead?
That would be to find the age of the fossil. Its called radiometric dating.