What is the mass number of an ion with 109 electrons, 158 neutrons, and a +1 charge

The mass number is 267.

Explanation:

It is given that,

Number of electrons are 109

Number of neutrons are 158

Charge is +1

We need to find the mass number of the ion.

We know that,

Mass number =  No. of neutrons+ No. of protons

Also, No. of protons = No. of electrons = 109

So,

Mass number = 109+158 = 267

Therefore, the mass number is 267.

it should be d) transitional fossils.

they show the gradualism of evolution throughout a period of time

to this one it would be receptive field