I already answered your question. Verbs are not gender specific like nouns.
Necesitar - to need
Yo necesito - I need
Tú necesitas - You need
Él/Ella necesita - He/She needs. Also note that any time you see 'the boy, girl, man, woman it will also always be necesita as with the current sample question. This form is also used with usted, the formal you(used when addressing strangers or people of authority like police).
Verbs don't care if the person you are speaking to is male or female nor does it care if what you speak about is male or female. The verb endings will never change to suit a gender.
In european spanish the 'b' and 'v' are almost indistinct (native speakers say a 'bv' in almost every case for either). However, in the Americas the spanish spoken there typically favours the strong v-like pronunciations, and given Duo's english is heavily americanised a strong 'v' sound would be likely the more common of the two. So you'd be right in thinking its dialectical, I hope this helps.
That's not true, there is no english V sound in Spanish, Latin Americans pronounce B & V with no distinction between them, and the same as Europeans. Both are pronounced as a hard B sound as in "Boy" after hard consonants when either is the first letter of a word at the beginning of a phrase, or after a pause; and a softer sound that may sound like a V to non-native speakers, but it's B pronounced with the lips not touching, when either appears in between vowels or after a word that ends in a vowel in the middle of phrases. The english V sound is usually used as a teaching mechanism so that learners don't misspell words by using the letters B and V interchangeable when writing.
No, Jack. In México it's also "B" before "N", "M" and at the start of the phrase and something between "B" and "V" for the other cases. And not only there. It should be everywhere because that's specifcally in the Spanish language. Just in Duolingo they pronounce the words separately and are like robots - you can notice when you hear the slower audio. But in some places in Central America and the Carribeans they pronounce it more like "V" when it's the English "V" but I'm not sure.
No one I know ever says bolígrafo. It sounds a bit pedantic to me but I guess that also depends on the region. In Mexico it's most common to say pluma if you're near the capital, if you go south people will say lapicero meaning pen but few will say pluma. The problem is that lapicero near the capital means mechanical pencil so... Dialects, what a problem. Learn whatever word you want and don't worry about duo marking things wrong.
I've learned that there are about a dozen words for pen in Spanish and as you mentioned, usage varies depending on the region. There are major disagreements about this in the English for Spanish speakers course. In real life, you can just hold up a pen and say, "¿Qué es esto? or something similar to figure out what it's called wherever you are located.
I always get confused with "necesita" and "necesito". I made a mistake one time, and I was told that the last letter in the verb is the same with the noun. Why is it now "necesita" for "niño" instead of "necesito"?
PS: I know "necesito" is also used for "yo". I just want to know why it cant be used for "niño".
Nouns and adjectives should match in number and gender, but verbs don't follow the same rules. You might consider checking a conjugation table such as https://www.spanishdict.com/conjugate/necesitar.
Necesito means "I need" but necesita means He/she/it needs. Necesitó does mean he/she/it needed but that's past tense.