One structure that can be found is most plant cells is chloroplast. A plant cell may have around 0 to 20 chloroplast, depending on their location in plant or their function.
Chloroplast is the structure that photosynthesis occurs. Photosynthesis is the method that plant make food for themselves. They turn sunlight into food such as starch.
Plants are autotrophs, which means they make food themselves, they don't need food from other sources like animals. Therefore, chloroplast is not found in animal cells because we are heterotrophs, we feed on other food.
Answer: Potassium-40 decays into argon gas over time.
Explanation: Potassium-argon dating is a dating method used to determine the age of sedimentary rocks by comparing the proportion of K-40 to Ar-40 in a sample of rock, and knowing the decay rate of K-40.
Potassium-40 undergoes decay following first order kinetics as given below:

Using Punnett Squares, you can predict the genotypes and phenotypes of the offspring<span> of a cross between a homozygous (purebred) tall pea plant and a homozygous (purebred) short pea plant.</span>
Answer:
(d). B-cells.
Explanation:
Adaptive immunity can be described as immunity which develops in response to exposure to a pathogen (or foreign molecule). throughout the life. It is divided into two types, humoral immunity and cell-mediated immunity.
Humoral immunity is mediated by B cells that secrete antibodies against particular antigens. These antibodies recognize and neutralize the antigens and activate cell-mediated immunity, which is mediated by T cells.
Thus, the correct answer is option (d).